FB 851 then BA 778 at Heathrow
Sofia → London → Stockholm
Timetable, London time
12:10FB 851 from Sofia at the gate
10:55BA 778 to Stockholm leaves the gate
22 h 45 apart on the timetable, overnight
BA 778 leaves 22 h 45 after FB 851 arrives on the timetable: more than half a day, so not a connection we count.