you can get a validation easily just by writing air law and doing a flight test, which is valid for a year, but as square leg said, in the long run it is better to get the SA CPL. For that you must write all the exams (8) and do the flight test, medical, CRM and dangerous goods.
The person to speak to is Claudia in the SACAA, as she deals with this sort of stuff (sorry, don't have her direct dial to hand) I tend to ignore their website, as they never seem to update it.
Good luck