BA 1401 then BA 762 at Heathrow
Belfast City → London → Basel
Timetable, London time
18:25BA 1401 from Belfast City at the gate
16:40BA 762 to Basel leaves the gate
22 h 15 apart on the timetable, overnight
BA 762 leaves 22 h 15 after BA 1401 arrives on the timetable: more than half a day, so not a connection we count.