SA 306 then SA 531 at Johannesburg
Cape Town → Johannesburg → Durban
Timetable, Johannesburg time
09:00SA 306 from Cape Town at the gate
07:30SA 531 to Durban leaves the gate
22 h 30 apart on the timetable, overnight
SA 531 leaves 22 h 30 after SA 306 arrives on the timetable: more than half a day, so not a connection we count.