BA 349 then BA 574 at Heathrow
Nice → London → Milan Linate
Timetable, London time
21:05BA 349 from Nice at the gate
14:50BA 574 to Milan Linate leaves the gate
17 h 45 apart on the timetable, overnight
BA 574 leaves 17 h 45 after BA 349 arrives on the timetable: more than half a day, so not a connection we count.