BA 801 then BA 544 at Heathrow
Reykjavík → London → Bologna
Timetable, London time
15:05BA 801 from Reykjavík at the gate
13:55BA 544 to Bologna leaves the gate
22 h 50 apart on the timetable, overnight
BA 544 leaves 22 h 50 after BA 801 arrives on the timetable: more than half a day, so not a connection we count.