BA 871 then BA 540 at Heathrow
Budapest → London → Bologna
Timetable, London time
09:05BA 871 from Budapest at the gate
08:05BA 540 to Bologna leaves the gate
23 h apart on the timetable, overnight
BA 540 leaves 23 h after BA 871 arrives on the timetable: more than half a day, so not a connection we count.