BA 483 then BA 748 at Heathrow
Barcelona → London → Geneva
Timetable, London time
19:25BA 483 from Barcelona at the gate
17:55BA 748 to Geneva leaves the gate
22 h 30 apart on the timetable, overnight
BA 748 leaves 22 h 30 after BA 483 arrives on the timetable: more than half a day, so not a connection we count.