BA 893 then UL 504 at Heathrow
Sofia → London → Colombo
Timetable, London time
21:50BA 893 from Sofia at the gate
20:40UL 504 to Colombo leaves the gate
22 h 50 apart on the timetable, overnight
UL 504 leaves 22 h 50 after BA 893 arrives on the timetable: more than half a day, so not a connection we count.