BA 339 then BA 804 at Heathrow
Nice → London → Dalaman
Timetable, London time
12:15BA 339 from Nice at the gate
11:55BA 804 to Dalaman leaves the gate
23 h 40 apart on the timetable, overnight
BA 804 leaves 23 h 40 after BA 339 arrives on the timetable: more than half a day, so not a connection we count.