The 24-hour servos are Port Augusta, Coober Pedy, Marla, Alice Springs, Tennant Creek, Katherine, Darwin.
You'll need at least one receipt between Tennant Creek and Katherine as the distance is greater than the 600 km IBA-imposed limit. Renner Springs has a 24-hour fuel card system but I don't rely on card systems. You can still stop there for a receipt from the pub if the pumps are not working.
PM me if you want a copy of my detailed Excel spreadsheets for the Centreline 24.