IB 719 then BA 762 at Heathrow
Madrid → London → Basel
Timetable, London time
16:35IB 719 from Madrid at the gate
16:00BA 762 to Basel leaves the gate
23 h 25 apart on the timetable, overnight
BA 762 leaves 23 h 25 after IB 719 arrives on the timetable: more than half a day, so not a connection we count.