BA 274 then BA 746 at Heathrow
Las Vegas → London → Geneva
Timetable, London time
14:50BA 274 from Las Vegas at the gate
10:30BA 746 to Geneva leaves the gate
19 h 40 apart on the timetable, overnight
BA 746 leaves 19 h 40 after BA 274 arrives on the timetable: more than half a day, so not a connection we count.