SQ 505 then SQ 318 at Changi
Ahmedabad → Singapore → London Heathrow
Timetable, Singapore time
17:10SQ 505 from Ahmedabad at the gate
12:45SQ 318 to London Heathrow leaves the gate
19 h 35 apart on the timetable, overnight
SQ 318 leaves 19 h 35 after SQ 505 arrives on the timetable: more than half a day, so not a connection we count.