BA 349 then IB 724 at Heathrow
Nice → London → Madrid
Timetable, London time
21:05BA 349 from Nice at the gate
19:05IB 724 to Madrid leaves the gate
22 h apart on the timetable, overnight
IB 724 leaves 22 h after BA 349 arrives on the timetable: more than half a day, so not a connection we count.