BA 349 then A3 605 at Heathrow
Nice → London → Athens
Timetable, London time
21:05BA 349 from Nice at the gate
19:00A3 605 to Athens leaves the gate
21 h 55 apart on the timetable, overnight
A3 605 leaves 21 h 55 after BA 349 arrives on the timetable: more than half a day, so not a connection we count.