BA 703 then BA 872 at Heathrow
Vienna → London → Krakow
Timetable, London time
09:30BA 703 from Vienna at the gate
06:05BA 872 to Krakow leaves the gate
20 h 35 apart on the timetable, overnight
BA 872 leaves 20 h 35 after BA 703 arrives on the timetable: more than half a day, so not a connection we count.