BA 1497 then SQ 305 at Heathrow
Glasgow → London → Singapore
Timetable, London time
09:35BA 1497 from Glasgow at the gate
09:10SQ 305 to Singapore leaves the gate
23 h 35 apart on the timetable, overnight
SQ 305 leaves 23 h 35 after BA 1497 arrives on the timetable: more than half a day, so not a connection we count.