FB 851 then BA 826 at Heathrow
Sofia → London → Dublin
Timetable, London time
16:45FB 851 from Sofia at the gate
12:50BA 826 to Dublin leaves the gate
20 h 05 apart on the timetable, overnight
BA 826 leaves 20 h 05 after FB 851 arrives on the timetable: more than half a day, so not a connection we count.