BA 1485 then VS 449 at Heathrow
Glasgow → London → Johannesburg
Timetable, London time
19:25BA 1485 from Glasgow at the gate
19:15VS 449 to Johannesburg leaves the gate
23 h 50 apart on the timetable, overnight
VS 449 leaves 23 h 50 after BA 1485 arrives on the timetable: more than half a day, so not a connection we count.