BA 485 then BA 352 at Heathrow
Barcelona → London → Nice
Timetable, London time
18:50BA 485 from Barcelona at the gate
18:05BA 352 to Nice leaves the gate
23 h 15 apart on the timetable, overnight
BA 352 leaves 23 h 15 after BA 485 arrives on the timetable: more than half a day, so not a connection we count.