Add Settings tab: distance units toggle, onboarding replay, £4.99 tip; drop E10/E5 from labels

- FuelType labels: 'Unleaded (E10)'/'Premium (E5)' -> 'Unleaded'/'Premium'
- New DistanceUnit (miles/km) preference; all app + widget distances,
  radii and alert text convert/display in the chosen unit
- Settings tab (4th tab): segmented miles/km picker, 'Show introduction'
  replay button (onboarding moved out of Alerts tab), StoreKit tip £4.99
- ProximityMonitor + widget notifications use the chosen unit
- Tests: label expectations updated, DistanceUnit conversion + format tests

FuelBoard/AlertsView.swift

@@ -4,10 +4,14 @@ import SwiftUI
 /// being monitored.
 struct AlertsView: View {
     @Binding var enabled: Bool
-    @Binding var radius: Double
+    @Binding var radius: Double   // stored in km (monitor + storage)
+    let distanceUnit: DistanceUnit
     let monitoredCount: Int
     let lastAlert: String?
-    var onShowOnboarding: () -> Void = {}
+
+    /// The radius slider works in the user's chosen unit; the stored value
+    /// stays km so ProximityMonitor and persistence never change.
+    private var radiusInUnit: Double { distanceUnit.fromKM(radius) }
 
     var body: some View {
         NavigationStack {
@@ -24,11 +28,15 @@ struct AlertsView: View {
                             HStack {
                                 Text("Radius")
                                 Spacer()
-                                Text("\(Int(radius)) km")
+                                Text(String(format: "%.1f %@", radiusInUnit, distanceUnit.shortName))
                                     .foregroundStyle(.secondary)
                                     .monospacedDigit()
                             }
-                            Slider(value: $radius, in: 1...10, step: 1)
+                            // 1–10 in the user's unit; convert back to km on change.
+                            Slider(value: Binding(
+                                get: { radiusInUnit },
+                                set: { radius = distanceUnit.toKM($0) }
+                            ), in: 1...10, step: distanceUnit == .kilometers ? 1 : 0.5)
                         }
                     }
 
@@ -42,7 +50,7 @@ struct AlertsView: View {
                             Text("Your favourites get priority, then the closest stations fill the rest (18 max, iOS region limit).")
                                 .font(.caption)
                                 .foregroundStyle(.secondary)
-                            Text("Alerts are checked against the cheapest station within \(Int(radius)) km for the selected fuel. Each station alerts at most once per hour.")
+                            Text("Alerts are checked against the cheapest station within the trigger radius for the selected fuel. Each station alerts at most once per hour.")
                                 .font(.caption)
                                 .foregroundStyle(.secondary)
                         }
@@ -55,19 +63,6 @@ struct AlertsView: View {
                         }
                     }
                 }
-
-                // Testing hook — in production onboarding shows once at first
-                // launch; this button re-opens it to verify the flow.
-                Section {
-                    Button {
-                        onShowOnboarding()
-                    } label: {
-                        Label("Show onboarding (testing)", systemImage: "flag.fill")
-                            .font(.footnote)
-                    }
-                } footer: {
-                    Text("Testing only — onboarding normally appears once on first launch.")
-                }
             }
             .navigationTitle("Alerts")
         }

FuelBoard/ContentView.swift

@@ -9,6 +9,7 @@ struct ContentView: View {
     @State private var selectedFuel: FuelType = FuelStore.loadSelectedFuel()
     @State private var sortMode: SortMode = FuelStore.loadSortMode()
     @State private var stationLimit: Int = FuelStore.loadStationLimit()
+    @State private var distanceUnit: DistanceUnit = FuelStore.loadDistanceUnit()
     @State private var favourites: [FuelStation] = FuelStore.loadFavourites()
     @State private var alertsEnabled: Bool = FuelStore.loadAlertsEnabled()
     @State private var alertsRadius: Double = FuelStore.loadAlertsRadius()
@@ -31,7 +32,7 @@ struct ContentView: View {
         let selling = stations.filter { $0.prices[selectedFuel] != nil }
         guard let location else { return selling }
         if sortMode == .closest { return selling }  // radius disabled in Closest
-        let radiusKM = Double(stationLimit) * 1.60934  // chosen miles → km
+        let radiusKM = distanceUnit.toKM(Double(stationLimit))  // chosen units → km
         return selling.filter {
             $0.distanceKM(to: location.lat, lng2: location.lng) <= radiusKM
         }
@@ -47,7 +48,7 @@ struct ContentView: View {
     private var baselinePrice: Double? {
         let pool = poolStations
         if sortMode == .closest, let location {
-            let radiusKM = Double(stationLimit) * 1.60934  // chosen miles → km
+            let radiusKM = distanceUnit.toKM(Double(stationLimit))  // chosen units → km
             let within = pool.filter {
                 $0.distanceKM(to: location.lat, lng2: location.lng) <= radiusKM
             }
@@ -111,6 +112,7 @@ struct ContentView: View {
                 selectedFuel: $selectedFuel,
                 sortMode: $sortMode,
                 stationLimit: $stationLimit,
+                distanceUnit: distanceUnit,
                 baselinePrice: baselinePrice,
                 topStationID: topStationID,
                 location: location,
@@ -124,6 +126,7 @@ struct ContentView: View {
                 favourites: refreshedFavourites,
                 selectedFuel: selectedFuel,
                 location: location,
+                distanceUnit: distanceUnit,
                 favouriteIDs: favouriteIDs,
                 onToggleFavourite: toggleFavourite
             )
@@ -132,11 +135,17 @@ struct ContentView: View {
             AlertsView(
                 enabled: $alertsEnabled,
                 radius: $alertsRadius,
+                distanceUnit: distanceUnit,
                 monitoredCount: monitor.monitoredStationIDs.count,
-                lastAlert: monitor.lastAlert,
+                lastAlert: monitor.lastAlert
-                onShowOnboarding: { showOnboarding = true }
             )
             .tabItem { Label("Alerts", systemImage: "bell.fill") }
+
+            SettingsView(
+                distanceUnit: $distanceUnit,
+                onShowOnboarding: { showOnboarding = true }
+            )
+            .tabItem { Label("Settings", systemImage: "gearshape.fill") }
         }
         .fullScreenCover(isPresented: $showOnboarding) {
             OnboardingView {
@@ -191,8 +200,9 @@ struct ContentView: View {
         }
         .onChange(of: stationLimit) { _, newValue in
             // Distance filter is LOCAL math now — the cache holds the full-UK
-            // dump, so changing 5/10/15 miles never needs a network fetch.
+            // dump, so changing 5/10/15 (miles or km) never needs a network
-            // sortedStations/radiusScopedStations recompute on the next render.
+            // fetch. sortedStations/radiusScopedStations recompute on the
+            // next render.
             FuelStore.saveStationLimit(newValue)
             WidgetCenter.shared.reloadAllTimelines()
         }
@@ -259,6 +269,7 @@ struct StationRow: View {
     let station: FuelStation
     let fuel: FuelType
     let location: Coordinate?
+    let distanceUnit: DistanceUnit
     let baselinePrice: Double?
     let isTopResult: Bool
     let isFavourite: Bool
@@ -325,7 +336,7 @@ struct StationRow: View {
                     .lineLimit(1)
                     .truncationMode(.tail)
                 if let location {
-                    Text(String(format: "%.1f mi", station.distanceKM(to: location.lat, lng2: location.lng) * 0.621371))
+                    Text(distanceUnit.format(station.distanceKM(to: location.lat, lng2: location.lng)))
                         .font(.caption2)
                         .foregroundStyle(.secondary)
                         .monospacedDigit()

FuelBoard/FavouritesView.swift

@@ -6,6 +6,7 @@ struct FavouritesView: View {
     let favourites: [FuelStation]
     let selectedFuel: FuelType
     let location: Coordinate?
+    let distanceUnit: DistanceUnit
     let favouriteIDs: Set<String>
     var onToggleFavourite: (FuelStation) -> Void = { _ in }
 
@@ -62,6 +63,7 @@ struct FavouritesView: View {
                                 station: station,
                                 fuel: selectedFuel,
                                 location: location,
+                                distanceUnit: distanceUnit,
                                 baselinePrice: cheapestPrice,
                                 isTopResult: index == 0,
                                 isFavourite: favouriteIDs.contains(station.id),

FuelBoard/OnboardingView.swift

@@ -94,7 +94,7 @@ struct OnboardingView: View {
                 .padding(.top, 12)
 
             featureRow(icon: "globe.europe.africa.fill", text: "England-wide prices — 8,000+ stations, updated twice a day")
-            featureRow(icon: "scope", text: "Cheapest within 5/10/15 miles, or closest station first")
+            featureRow(icon: "scope", text: "Cheapest within your chosen radius, or closest station first")
             featureRow(icon: "star.fill", text: "Favourites with instant price comparison")
             featureRow(icon: "chart.bar.fill", text: "Green/amber/red rating vs the best nearby price")
             featureRow(icon: "square.grid.2x2.fill", text: "Home-screen widget showing the cheapest nearby")

FuelBoard/ProximityMonitor.swift

@@ -155,14 +155,15 @@ final class ProximityMonitor: NSObject, ObservableObject, @preconcurrency CLLoca
 
     private func fireAlert(for station: FuelStation, price: Double) {
         let brand = station.brand.isEmpty ? station.name : station.brand
+        let unit = FuelStore.loadDistanceUnit()
         let content = UNMutableNotificationContent()
         content.title = "Cheapest \(fuel.displayName) nearby: \(brand)"
-        content.body = "\(station.name) is the cheapest within \(Int(radiusKM)) km at \(String(format: "%.1fp", price)). Tap to open."
+        content.body = "\(station.name) is the cheapest within \(unit.format(radiusKM)) at \(String(format: "%.1fp", price)). Tap to open."
         content.sound = .default
 
         let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: nil)
         UNUserNotificationCenter.current().add(request)
 
-        lastAlert = "\(brand) · \(String(format: "%.1fp", price)) · \(Int(radiusKM)) km radius"
+        lastAlert = "\(brand) · \(String(format: "%.1fp", price)) · \(unit.format(radiusKM)) radius"
     }
 }

FuelBoard/SettingsView.swift

@@ -0,0 +1,141 @@
+import SwiftUI
+import StoreKit
+import WidgetKit
+
+/// Settings tab — distance units, onboarding replay, and a tip jar.
+struct SettingsView: View {
+    @Binding var distanceUnit: DistanceUnit
+    var onShowOnboarding: () -> Void = {}
+
+    @StateObject private var tipStore = TipStore()
+    @State private var showTipAlert = false
+    @State private var tipAlertMessage = ""
+
+    var body: some View {
+        NavigationStack {
+            List {
+                Section {
+                    Picker("Distance", selection: $distanceUnit) {
+                        ForEach(DistanceUnit.allCases) { unit in
+                            Text(unit.displayName).tag(unit)
+                        }
+                    }
+                    .pickerStyle(.segmented)
+                    .onChange(of: distanceUnit) { _, newValue in
+                        FuelStore.saveDistanceUnit(newValue)
+                        WidgetCenter.shared.reloadAllTimelines()
+                    }
+                } header: {
+                    Text("Units")
+                } footer: {
+                    Text("Distances and search radii across the app, widget and alerts are shown in this unit.")
+                }
+
+                Section {
+                    Button {
+                        onShowOnboarding()
+                    } label: {
+                        Label("Show introduction", systemImage: "sparkles")
+                    }
+                } footer: {
+                    Text("Replay the welcome screen, including the location and notification permission prompts.")
+                }
+
+                Section {
+                    Button {
+                        Task { await tipStore.purchase() }
+                    } label: {
+                        HStack {
+                            Label("Leave a tip", systemImage: "heart.fill")
+                                .foregroundStyle(.pink)
+                            Spacer()
+                            Text(tipStore.displayPrice)
+                                .foregroundStyle(.secondary)
+                                .monospacedDigit()
+                        }
+                    }
+                    .disabled(tipStore.purchaseInProgress)
+                } header: {
+                    Text("Support FuelBoard")
+                } footer: {
+                    Text("A small tip helps keep the data relay and app development going. Thank you!")
+                }
+
+                if let message = tipStore.message {
+                    Section {
+                        Text(message)
+                            .font(.footnote)
+                            .foregroundStyle(.secondary)
+                    }
+                }
+            }
+            .navigationTitle("Settings")
+            .onAppear {
+                Task { await tipStore.load() }
+            }
+        }
+    }
+}
+
+/// Loads the £4.99 tip product and drives its purchase.
+@MainActor
+final class TipStore: ObservableObject {
+    /// Product ID for the £4.99 tip (App Store Connect — consumable).
+    static let productID = "com.apt.fuelboard.tip499"
+
+    @Published private(set) var product: Product?
+    @Published private(set) var purchaseInProgress = false
+    @Published private(set) var message: String?
+
+    var displayPrice: String {
+        product?.displayPrice ?? "£4.99"
+    }
+
+    func load() async {
+        // Refreshes product state on every visit so a newly-approved product
+        // (or a restored transaction) is picked up.
+        do {
+            let products = try await Product.products(for: [Self.productID])
+            product = products.first
+        } catch {
+            // No product yet (sideloaded build) — the button still shows the
+            // intended price and reports the purchase attempt gracefully.
+            product = nil
+        }
+    }
+
+    func purchase() async {
+        guard !purchaseInProgress else { return }
+        purchaseInProgress = true
+        defer { purchaseInProgress = false }
+
+        // If the product hasn't loaded (e.g. not configured in App Store
+        // Connect yet), still allow the attempt so the user sees a clear
+        // outcome rather than a dead button.
+        guard let product else {
+            message = "The tip isn't available in this build yet — check back after an App Store release."
+            return
+        }
+
+        do {
+            let result = try await product.purchase()
+            switch result {
+            case .success(let verification):
+                switch verification {
+                case .verified:
+                    message = "Thank you! Your tip has been received. ⛽"
+                case .unverified:
+                    message = "The purchase couldn't be verified. Please try again."
+                }
+            case .userCancelled:
+                message = nil   // silent — the user just closed the sheet
+            case .pending:
+                message = "Your tip is pending approval. It'll finish automatically."
+            @unknown default:
+                message = nil
+            }
+        } catch {
+            message = "The tip couldn't be completed: \(error.localizedDescription)"
+        }
+    }
+}

FuelBoard/StationsView.swift

@@ -9,6 +9,7 @@ struct StationsView: View {
     @Binding var selectedFuel: FuelType
     @Binding var sortMode: SortMode
     @Binding var stationLimit: Int
+    let distanceUnit: DistanceUnit
     let baselinePrice: Double?
     let topStationID: String?
     let location: Coordinate?
@@ -29,11 +30,11 @@ struct StationsView: View {
                 Section {
                     if let location {
                         if sortMode == .closest {
-                            Text("Closest \(selectedFuel.displayName) stations — nearest first, best value within \(stationLimit) miles.")
+                            Text("Closest \(selectedFuel.displayName) stations — nearest first, best value within \(stationLimit) \(distanceUnit.label).")
                                 .font(.footnote)
                                 .foregroundStyle(.secondary)
                         } else {
-                            Text("Cheapest \(selectedFuel.displayName) within \(stationLimit) miles — tap a station for directions.")
+                            Text("Cheapest \(selectedFuel.displayName) within \(stationLimit) \(distanceUnit.label) — tap a station for directions.")
                                 .font(.footnote)
                                 .foregroundStyle(.secondary)
                         }
@@ -60,7 +61,7 @@ struct StationsView: View {
                 Section("Distance") {
                     Picker("Distance", selection: $stationLimit) {
                         ForEach(FuelStore.stationRadiusOptions, id: \.self) { miles in
-                            Text("\(miles) miles").tag(miles)
+                            Text("\(miles) \(distanceUnit.label)").tag(miles)
                         }
                     }
                     .pickerStyle(.segmented)
@@ -79,7 +80,7 @@ struct StationsView: View {
                             .font(.caption2)
                             .foregroundStyle(.secondary)
                     } else {
-                        Text("\(totalCount) stations within \(stationLimit) miles")
+                        Text("\(totalCount) stations within \(stationLimit) \(distanceUnit.label)")
                             .font(.caption2)
                             .foregroundStyle(.secondary)
                     }
@@ -111,6 +112,7 @@ struct StationsView: View {
                                 station: station,
                                 fuel: selectedFuel,
                                 location: location,
+                                distanceUnit: distanceUnit,
                                 baselinePrice: baselinePrice,
                                 isTopResult: station.id == topStationID,
                                 isFavourite: favouriteIDs.contains(station.id),
@@ -193,12 +195,12 @@ struct StationsView: View {
 // MARK: - Fuel-type iconography (app target only — FuelStore.swift is Foundation-only)
 
 extension FuelType {
-    /// Short segment label ("Unleaded (E10)" / "Premium (E5)" / "Diesel") for
+    /// Short segment label ("Unleaded" / "Premium" / "Diesel") for
     /// the picker and description.
     var shortName: String {
         switch self {
-        case .e10: return "Unleaded (E10)"
+        case .e10: return "Unleaded"
-        case .e5: return "Premium (E5)"
+        case .e5: return "Premium"
         case .diesel: return "Diesel"
         }
     }

FuelBoardTests/Tests/FuelBoardSharedTests/FuelBoardTests.swift

@@ -196,10 +196,23 @@ final class BrandTests: XCTestCase {
 
 final class FuelTypeLabelTests: XCTestCase {
     func testDisplayNames() {
-        XCTAssertEqual(FuelType.e10.displayName, "Unleaded (E10)")
+        // E10/E5 grades are intentionally not part of user-facing labels.
-        XCTAssertEqual(FuelType.e5.displayName, "Premium (E5)")
+        XCTAssertEqual(FuelType.e10.displayName, "Unleaded")
+        XCTAssertEqual(FuelType.e5.displayName, "Premium")
         XCTAssertEqual(FuelType.diesel.displayName, "Diesel")
     }
+
+    func testDistanceUnitConversion() {
+        XCTAssertEqual(DistanceUnit.miles.toKM(1), 1.60934, accuracy: 0.00001)
+        XCTAssertEqual(DistanceUnit.kilometers.toKM(5), 5)
+        XCTAssertEqual(DistanceUnit.miles.fromKM(1.60934), 1, accuracy: 0.00001)
+        XCTAssertEqual(DistanceUnit.kilometers.fromKM(2.5), 2.5)
+    }
+
+    func testDistanceUnitFormat() {
+        XCTAssertEqual(DistanceUnit.miles.format(1.60934), "1.0 mi")
+        XCTAssertEqual(DistanceUnit.kilometers.format(3.4), "3.4 km")
+    }
 }
 
 final class FavouriteRefreshTests: XCTestCase {

FuelBoardWidgets/FuelPriceWidget.swift

@@ -36,15 +36,17 @@ struct FuelPriceEntry: TimelineEntry {
     let fuel: FuelType
     let location: Coordinate?
     let locationSource: String    // "live" | "cached" | "none"
+    let unit: DistanceUnit        // user's display unit for distances
 }
 
 struct FuelPriceTimelineProvider: TimelineProvider {
     func placeholder(in context: Context) -> FuelPriceEntry {
         let fuel = FuelStore.loadSelectedFuel()
+        let unit = FuelStore.loadDistanceUnit()
         let sample = SampleFuelProvider.sampleStations
             .filter { $0.prices[fuel] != nil }
             .sorted { $0.prices[fuel]! < $1.prices[fuel]! }
-        return FuelPriceEntry(date: Date(), stations: Array(sample.prefix(4)), fuel: fuel, location: nil, locationSource: "none")
+        return FuelPriceEntry(date: Date(), stations: Array(sample.prefix(4)), fuel: fuel, location: nil, locationSource: "none", unit: unit)
     }
 
     func getSnapshot(in context: Context, completion: @escaping (FuelPriceEntry) -> Void) {
@@ -85,11 +87,12 @@ struct FuelPriceTimelineProvider: TimelineProvider {
         }
 
         // 3) Load stations, then sort by price (distance tiebreak), scoped to
-        // the chosen search radius (miles) so the widget's "cheapest" matches
+        // the chosen search radius so the widget's "cheapest" matches
         // the app's list.
         var stations = FuelStore.loadStations()
         if stations.isEmpty { stations = SampleFuelProvider.sampleStations }
-        let radiusKM = Double(FuelStore.loadStationLimit()) * 1.60934  // miles → km
+        let unit = FuelStore.loadDistanceUnit()
+        let radiusKM = unit.toKM(Double(FuelStore.loadStationLimit()))  // chosen units → km
         if let location {
             // STRICT: cached data fetched around another location must never
             // leak out-of-radius stations into the widget.
@@ -112,7 +115,7 @@ struct FuelPriceTimelineProvider: TimelineProvider {
             sorted = filtered.sorted { $0.prices[fuel]! < $1.prices[fuel]! }
         }
 
-        return FuelPriceEntry(date: Date(), stations: Array(sorted.prefix(4)), fuel: fuel, location: location, locationSource: source)
+        return FuelPriceEntry(date: Date(), stations: Array(sorted.prefix(4)), fuel: fuel, location: location, locationSource: source, unit: FuelStore.loadDistanceUnit())
     }
 }
 
@@ -158,7 +161,7 @@ struct FuelPriceWidgetView: View {
                     .foregroundStyle(.green)
             }
             if let location = entry.location {
-                Text(String(format: "%.1f mi away", station.distanceKM(to: location.lat, lng2: location.lng) * 0.621371))
+                Text(entry.unit.format(station.distanceKM(to: location.lat, lng2: location.lng)) + " away")
                     .font(.caption2)
                     .foregroundStyle(.secondary)
             } else {
@@ -192,7 +195,7 @@ struct FuelPriceWidgetView: View {
                             .font(.caption.weight(.semibold))
                             .lineLimit(1)
                         if let location = entry.location {
-                            Text(String(format: "%.1f km", station.distanceKM(to: location.lat, lng2: location.lng)))
+                            Text(entry.unit.format(station.distanceKM(to: location.lat, lng2: location.lng)))
                                 .font(.caption2)
                                 .foregroundStyle(.secondary)
                         }

Shared/FuelStore.swift

@@ -48,21 +48,75 @@ enum RAGRating: Int, Codable {
 }
 
 enum FuelType: String, Codable, CaseIterable, Identifiable {
-    case e10    // Unleaded 95 (E10)
+    case e10    // Unleaded (E10)
-    case e5     // Premium 97/98 (E5)
+    case e5     // Premium (E5)
     case diesel // B7 diesel
 
     var id: String { rawValue }
 
     var displayName: String {
         switch self {
-        case .e10: return "Unleaded (E10)"
+        case .e10: return "Unleaded"
-        case .e5: return "Premium (E5)"
+        case .e5: return "Premium"
         case .diesel: return "Diesel"
         }
     }
 }
 
+/// Display unit for all distances in the app + widget. Internally distances
+/// are always stored/computed in km; conversion happens at the display and
+/// filter boundary so nothing else needs to know the unit.
+enum DistanceUnit: String, Codable, CaseIterable, Identifiable {
+    case miles
+    case kilometers
+
+    var id: String { rawValue }
+
+    var displayName: String {
+        switch self {
+        case .miles: return "Miles"
+        case .kilometers: return "Kilometres"
+        }
+    }
+
+    /// Short suffix for values ("5 mi", "3.2 km").
+    var shortName: String {
+        switch self {
+        case .miles: return "mi"
+        case .kilometers: return "km"
+        }
+    }
+
+    /// Full word for narrative text ("within 5 miles", "within 8 km").
+    var label: String {
+        switch self {
+        case .miles: return "miles"
+        case .kilometers: return "km"
+        }
+    }
+
+    /// Convert a value expressed in this unit to km.
+    func toKM(_ value: Double) -> Double {
+        switch self {
+        case .miles: return value * 1.60934
+        case .kilometers: return value
+        }
+    }
+
+    /// Convert a km value to this unit.
+    func fromKM(_ km: Double) -> Double {
+        switch self {
+        case .miles: return km * 0.621371
+        case .kilometers: return km
+        }
+    }
+
+    /// Format a km distance in this unit ("1.2 mi", "3.4 km").
+    func format(_ km: Double) -> String {
+        String(format: "%.1f %@", fromKM(km), shortName)
+    }
+}
+
 // MARK: - Station model
 
 struct FuelStation: Identifiable, Codable, Equatable {
@@ -179,6 +233,7 @@ struct FuelStore {
     static let fuelKey = "fuelboard.selectedFuel"      // FuelType raw value
     static let sortModeKey = "fuelboard.sortMode"      // SortMode raw value
     static let stationLimitKey = "fuelboard.stationLimitMiles" // Int miles (5/10/15)
+    static let distanceUnitKey = "fuelboard.distanceUnit"      // DistanceUnit raw value
     static let favouritesKey = "fuelboard.favourites"      // [FuelStation] JSON
     static let alertsEnabledKey = "fuelboard.alertsEnabled" // Bool
     static let alertsRadiusKey = "fuelboard.alertsRadius"   // Double km
@@ -277,6 +332,20 @@ struct FuelStore {
         saveString(String(miles), service: stationLimitKey)
     }
 
+    // MARK: Distance unit — miles or kilometres. Stored raw value; default
+    // miles for backward compatibility with pre-toggle installs.
+
+    static func loadDistanceUnit() -> DistanceUnit {
+        if let raw = loadString(service: distanceUnitKey), let unit = DistanceUnit(rawValue: raw) {
+            return unit
+        }
+        return .miles
+    }
+
+    static func saveDistanceUnit(_ unit: DistanceUnit) {
+        saveString(unit.rawValue, service: distanceUnitKey)
+    }
+
     // MARK: Favourites
 
     static func loadFavourites() -> [FuelStation] {