Sorry it's taken a while - rough directions to Scott's grave from my contact in South Africa, hope they're of some use:
It's in the Anglican section. That is opposite the Old Greys Hospital and backs on to Miller street.
From the Lych gate it is probably easiest to take the second pathway facing left (North) …walk right to the end boundary wall,(nearest grave is Buntine/Pinson…. face north- east and travel past 3 main blocks of graves and turn right,:
graves then are Matthews; Coates;Broome: The Scott graves are in a strange diagonal block, before William.