FB 851 then EI 153 at Heathrow
Sofia → London → Dublin
Timetable, London time
12:10FB 851 from Sofia at the gate
08:50EI 153 to Dublin leaves the gate
20 h 40 apart on the timetable, overnight
EI 153 leaves 20 h 40 after FB 851 arrives on the timetable: more than half a day, so not a connection we count.