BA 551 then BA 544 at Heathrow
Rome → London → Bologna
Timetable, London time
14:05BA 551 from Rome at the gate
13:55BA 544 to Bologna leaves the gate
23 h 50 apart on the timetable, overnight
BA 544 leaves 23 h 50 after BA 551 arrives on the timetable: more than half a day, so not a connection we count.