BA 1401 then EI 173 at Heathrow
Belfast City → London → Dublin
Timetable, London time
18:25BA 1401 from Belfast City at the gate
17:45EI 173 to Dublin leaves the gate
23 h 20 apart on the timetable, overnight
EI 173 leaves 23 h 20 after BA 1401 arrives on the timetable: more than half a day, so not a connection we count.