BA 585 then UL 504 at Heathrow
Milan Linate → London → Colombo
Timetable, London time
21:30BA 585 from Milan Linate at the gate
20:40UL 504 to Colombo leaves the gate
23 h 10 apart on the timetable, overnight
UL 504 leaves 23 h 10 after BA 585 arrives on the timetable: more than half a day, so not a connection we count.