BA 339 then EI 159 at Heathrow
Nice → London → Dublin
Timetable, London time
12:15BA 339 from Nice at the gate
12:10EI 159 to Dublin leaves the gate
23 h 55 apart on the timetable, overnight
EI 159 leaves 23 h 55 after BA 339 arrives on the timetable: more than half a day, so not a connection we count.