FB 851 then SK 806 at Heathrow
Sofia → London → Oslo
Timetable, London time
16:55FB 851 from Sofia at the gate
15:35SK 806 to Oslo leaves the gate
22 h 40 apart on the timetable, overnight
SK 806 leaves 22 h 40 after FB 851 arrives on the timetable: more than half a day, so not a connection we count.