BA 579 then BA 746 at Heathrow
Milan Linate → London → Geneva
Timetable, London time
16:30BA 579 from Milan Linate at the gate
10:30BA 746 to Geneva leaves the gate
18 h apart on the timetable, overnight
BA 746 leaves 18 h after BA 579 arrives on the timetable: more than half a day, so not a connection we count.