EI 172 then BA 638 at Heathrow
Dublin → London → Athens
Timetable, London time
16:50EI 172 from Dublin at the gate
16:15BA 638 to Athens leaves the gate
23 h 25 apart on the timetable, overnight
BA 638 leaves 23 h 25 after EI 172 arrives on the timetable: more than half a day, so not a connection we count.