BA 1391 then BA 770 at Heathrow
Belfast City → London → Oslo
Timetable, London time
10:45BA 1391 from Belfast City at the gate
10:20BA 770 to Oslo leaves the gate
23 h 35 apart on the timetable, overnight
BA 770 leaves 23 h 35 after BA 1391 arrives on the timetable: more than half a day, so not a connection we count.