BA 463 then BA 746 at Heathrow
Madrid → London → Geneva
Timetable, London time
16:05BA 463 from Madrid at the gate
10:30BA 746 to Geneva leaves the gate
18 h 25 apart on the timetable, overnight
BA 746 leaves 18 h 25 after BA 463 arrives on the timetable: more than half a day, so not a connection we count.