BA 391 then BA 742 at Heathrow
Brussels → London → Geneva
Timetable, London time
15:10BA 391 from Brussels at the gate
15:05BA 742 to Geneva leaves the gate
23 h 55 apart on the timetable, overnight
BA 742 leaves 23 h 55 after BA 391 arrives on the timetable: more than half a day, so not a connection we count.