U2 878 then U2 839 at Gatwick
Saint Helier → London → Castletown
Timetable, London time
17:30U2 878 from Saint Helier at the gate
08:35U2 839 to Castletown leaves the gate
15 h 05 apart on the timetable, overnight
U2 839 leaves 15 h 05 after U2 878 arrives on the timetable: more than half a day, so not a connection we count.