All good

frontend/src/components/map/JourneyInstructions.tsx

@@ -68,6 +68,34 @@ const ROUTE_COLORS: Record<string, { color: string; darkText?: boolean }> = {
 };
 
 const NON_TUBE_NAMES = new Set(['DLR', 'London Overground', 'Elizabeth line']);
+const GOOGLE_MAPS_DEPARTURE_TIME_ZONE = 'Europe/London';
+const londonDateFormatter = new Intl.DateTimeFormat('en-GB', {
+  timeZone: GOOGLE_MAPS_DEPARTURE_TIME_ZONE,
+  year: 'numeric',
+  month: '2-digit',
+  day: '2-digit',
+});
+const londonDateTimeFormatter = new Intl.DateTimeFormat('en-GB', {
+  timeZone: GOOGLE_MAPS_DEPARTURE_TIME_ZONE,
+  year: 'numeric',
+  month: '2-digit',
+  day: '2-digit',
+  hour: '2-digit',
+  minute: '2-digit',
+  second: '2-digit',
+  hour12: false,
+  hourCycle: 'h23',
+});
+
+function dateTimeParts(formatter: Intl.DateTimeFormat, date: Date): Record<string, number> {
+  const parts: Record<string, number> = {};
+  formatter.formatToParts(date).forEach((part) => {
+    if (part.type !== 'literal') {
+      parts[part.type] = Number(part.value);
+    }
+  });
+  return parts;
+}
 
 /** Strip trailing parenthesized GTFS route IDs and NaPTAN stop codes (e.g. "(6757261)", "(9400ZZLUCGT1)") */
 function stripId(label: string): string {
@@ -87,15 +115,48 @@ function getRouteDisplay(mode: string): { label: string; color: string; darkText
   return { label: clean, color: '#6b7280', darkText: false };
 }
 
-/** Returns a Unix timestamp for the next Monday at 07:30 local time. */
+function londonOffsetMs(utcMs: number): number {
+  const parts = dateTimeParts(londonDateTimeFormatter, new Date(utcMs));
+  const londonAsUtcMs = Date.UTC(
+    parts.year,
+    parts.month - 1,
+    parts.day,
+    parts.hour,
+    parts.minute,
+    parts.second
+  );
+  return londonAsUtcMs - utcMs;
+}
+
+function londonTimeToUtcMs(
+  year: number,
+  month: number,
+  day: number,
+  hour: number,
+  minute: number
+): number {
+  const localAsUtcMs = Date.UTC(year, month - 1, day, hour, minute, 0, 0);
+  const offsetMs = londonOffsetMs(localAsUtcMs);
+  const utcMs = localAsUtcMs - offsetMs;
+  const correctedOffsetMs = londonOffsetMs(utcMs);
+  return correctedOffsetMs === offsetMs ? utcMs : localAsUtcMs - correctedOffsetMs;
+}
+
+/** Returns a Unix timestamp for the next Monday at 07:30 Europe/London time. */
 function nextMondayAt730(): number {
   const now = new Date();
-  const day = now.getDay(); // 0=Sun … 6=Sat
+  const today = dateTimeParts(londonDateFormatter, now);
+  const day = new Date(Date.UTC(today.year, today.month - 1, today.day)).getUTCDay();
   const daysUntil = day === 0 ? 1 : day === 1 ? 7 : 8 - day;
-  const monday = new Date(now);
-  monday.setDate(now.getDate() + daysUntil);
-  monday.setHours(7, 30, 0, 0);
-  return Math.floor(monday.getTime() / 1000);
+  const monday = new Date(Date.UTC(today.year, today.month - 1, today.day + daysUntil));
+  const utcMs = londonTimeToUtcMs(
+    monday.getUTCFullYear(),
+    monday.getUTCMonth() + 1,
+    monday.getUTCDate(),
+    7,
+    30
+  );
+  return Math.floor(utcMs / 1000);
 }
 
 function googleMapsDestination(

frontend/src/components/map/MapPage.tsx

@@ -419,6 +419,7 @@ export default function MapPage({
   const { listings: actualListings } = useActualListings(mapData.bounds, {
     filterParam: actualListingsFilterParam,
     travelParam: actualListingsTravelParam,
+    shareCode,
   });
   const [isAreaGroupExpanded, toggleAreaGroup] = useCollapsibleGroups(true);