BA 893 then BA 774 at Heathrow
Sofia → London → Oslo
Timetable, London time
21:50BA 893 from Sofia at the gate
18:55BA 774 to Oslo leaves the gate
21 h 05 apart on the timetable, overnight
BA 774 leaves 21 h 05 after BA 893 arrives on the timetable: more than half a day, so not a connection we count.