BA 1399 then EI 169 at Heathrow
Belfast City → London → Dublin
Timetable, London time
16:35BA 1399 from Belfast City at the gate
16:20EI 169 to Dublin leaves the gate
23 h 45 apart on the timetable, overnight
EI 169 leaves 23 h 45 after BA 1399 arrives on the timetable: more than half a day, so not a connection we count.