BA 349 then BA 864 at Heathrow
Nice → London → Prague
Timetable, London time
21:05BA 349 from Nice at the gate
19:50BA 864 to Prague leaves the gate
22 h 45 apart on the timetable, overnight
BA 864 leaves 22 h 45 after BA 349 arrives on the timetable: more than half a day, so not a connection we count.