U2 878 then U2 8243 at Gatwick
Saint Helier → London → Thessaloniki
Timetable, London time
18:00U2 878 from Saint Helier at the gate
16:05U2 8243 to Thessaloniki leaves the gate
22 h 05 apart on the timetable, overnight
U2 8243 leaves 22 h 05 after U2 878 arrives on the timetable: more than half a day, so not a connection we count.