EC 1703 then IB 717 at Madrid
Nice → Madrid → London Heathrow
Timetable, Madrid time
20:40EC 1703 from Nice at the gate
13:15IB 717 to London Heathrow leaves the gatealso LA 1539, VY 5179, QR 5345, BA 7056, AA 8755
16 h 35 apart on the timetable, overnight
IB 717 leaves 16 h 35 after EC 1703 arrives on the timetable: more than half a day, so not a connection we count.