FB 851 then SK 804 at Heathrow
Sofia → London → Oslo
Timetable, London time
16:45FB 851 from Sofia at the gate
10:35SK 804 to Oslo leaves the gate
17 h 50 apart on the timetable, overnight
SK 804 leaves 17 h 50 after FB 851 arrives on the timetable: more than half a day, so not a connection we count.