BA 591 then LX 319 at Heathrow
Venezia → London → Zurich
Timetable, London time
13:10BA 591 from Venezia at the gate
12:05LX 319 to Zurich leaves the gate
22 h 55 apart on the timetable, overnight
LX 319 leaves 22 h 55 after BA 591 arrives on the timetable: more than half a day, so not a connection we count.