BA 256 then BA 746 at Heathrow
New Delhi → London → Geneva
Timetable, London time
15:15BA 256 from New Delhi at the gate
10:30BA 746 to Geneva leaves the gate
19 h 15 apart on the timetable, overnight
BA 746 leaves 19 h 15 after BA 256 arrives on the timetable: more than half a day, so not a connection we count.