BA 873 then BA 1372 at Heathrow
Krakow → London → Manchester
Timetable, London time
18:05BA 873 from Krakow at the gate
15:20BA 1372 to Manchester leaves the gate
21 h 15 apart on the timetable, overnight
BA 1372 leaves 21 h 15 after BA 873 arrives on the timetable: more than half a day, so not a connection we count.