BA 473 then BA 746 at Heathrow
Barcelona → London → Geneva
Timetable, London time
11:40BA 473 from Barcelona at the gate
10:30BA 746 to Geneva leaves the gate
22 h 50 apart on the timetable, overnight
BA 746 leaves 22 h 50 after BA 473 arrives on the timetable: more than half a day, so not a connection we count.