BA 349 then BA 1370 at Heathrow
Nice → London → Manchester
Timetable, London time
21:05BA 349 from Nice at the gate
14:25BA 1370 to Manchester leaves the gate
17 h 20 apart on the timetable, overnight
BA 1370 leaves 17 h 20 after BA 349 arrives on the timetable: more than half a day, so not a connection we count.