BA 725 then BA 590 at Heathrow
Zurich → London → Venezia
Timetable, London time
07:45BA 725 from Zurich at the gate
06:10BA 590 to Venezia leaves the gate
22 h 25 apart on the timetable, overnight
BA 590 leaves 22 h 25 after BA 725 arrives on the timetable: more than half a day, so not a connection we count.