Hi Fivo,
I don't know of any venues in that area. When I go flysfishing for yellows I ussually got to the resorts in and around the Parys area in the Vaal. Closest such a resort would propably be in the Lindequestdrift area. But still it's a bit of a drive from Pretoria. I know that some people do fish parts of the crocodile and Magalies rivers for yellows. But I have no idea where. I can only help you out with a few places on the Vaal I ussually go to.