BA 1439 then SQ 317 at Heathrow
Edinburgh → London → Singapore
Timetable, London time
10:50BA 1439 from Edinburgh at the gate
10:40SQ 317 to Singapore leaves the gate
23 h 50 apart on the timetable, overnight
SQ 317 leaves 23 h 50 after BA 1439 arrives on the timetable: more than half a day, so not a connection we count.