BA 58 then FB 852 at Heathrow
Cape Town → London → Sofia
Timetable, London time
04:55BA 58 from Cape Town at the gate
17:55FB 852 to Sofia leaves the gate
13 h apart on the timetable
FB 852 leaves 13 h after BA 58 arrives on the timetable: more than half a day, so not a connection we count.