BA 252 then BA 746 at Heathrow
Grand Cayman → London → Geneva
Timetable, London time
11:15BA 252 from Grand Cayman at the gate
10:30BA 746 to Geneva leaves the gate
23 h 15 apart on the timetable, overnight
BA 746 leaves 23 h 15 after BA 252 arrives on the timetable: more than half a day, so not a connection we count.