FB 851 then KL 1006 at Heathrow
Sofia → London → Amsterdam
Timetable, London time
16:55FB 851 from Sofia at the gate
11:45KL 1006 to Amsterdam leaves the gate
18 h 50 apart on the timetable, overnight
KL 1006 leaves 18 h 50 after FB 851 arrives on the timetable: more than half a day, so not a connection we count.