BA 505 then BA 746 at Heathrow
Lisbon → London → Geneva
Timetable, London time
15:50BA 505 from Lisbon at the gate
10:30BA 746 to Geneva leaves the gate
18 h 40 apart on the timetable, overnight
BA 746 leaves 18 h 40 after BA 505 arrives on the timetable: more than half a day, so not a connection we count.