BA 349 then BA 816 at Heathrow
Nice → London → Copenhagen
Timetable, London time
21:05BA 349 from Nice at the gate
16:40BA 816 to Copenhagen leaves the gate
19 h 35 apart on the timetable, overnight
BA 816 leaves 19 h 35 after BA 349 arrives on the timetable: more than half a day, so not a connection we count.