FB 851 then QR 8 at Heathrow
Sofia → London → Doha
Timetable, London time
16:55FB 851 from Sofia at the gate
14:55QR 8 to Doha leaves the gate
22 h apart on the timetable, overnight
QR 8 leaves 22 h after FB 851 arrives on the timetable: more than half a day, so not a connection we count.