BA 541 then BA 510 at Heathrow
Bologna → London → Lisbon
Timetable, London time
15:35BA 541 from Bologna at the gate
15:00BA 510 to Lisbon leaves the gate
23 h 25 apart on the timetable, overnight
BA 510 leaves 23 h 25 after BA 541 arrives on the timetable: more than half a day, so not a connection we count.