The Jo'burg area is indeed quite lacking in suitable Navaids for IR training and the ILS at Lanseria is under heavy demand for training purposes as the one at Jo’burg International is not available for training and the one at Waterkloof is for the military only, the next closest is Durban!
However in the Eastern Cape where several large schools are situated there are:
Port Elizabeth: ILS, VOR, NDB, PAR & SRA approach facilities.
East London: ILS, VOR, NDB & SRA
There is generally low demand on these facilities as the frequency of scheduled flights is not high.