FB 851 then BA 1446 at Heathrow
Sofia → London → Edinburgh
Timetable, London time
16:45FB 851 from Sofia at the gate
11:05BA 1446 to Edinburgh leaves the gate
18 h 20 apart on the timetable, overnight
BA 1446 leaves 18 h 20 after FB 851 arrives on the timetable: more than half a day, so not a connection we count.