I have to say I found the museum very disappointing. The very helpful chap told me I would have been able to see the other exhibits if I came on a Saturday - but there was nothing to say that on their website - and I was going to be a couple of hundred miles away.... and I was there on a Friday
C'est la vie
Andy is quite correct - the museum at Ysterplaat is a bit disappointing with only the Ventura, Alouette, Vampire and Impala I on display. Unfortunately, the rest of the aircraft collection is on the operational side of the base and is not readily accessible to the public. Over the years, I've got to know the curator and he usually takes me live side if I am visiting Cape Town. Last time I visited, in 2011, the following aircraft were available for me to view - Mirage F1, Sikorsky S.55, Sabre, Impala I, Wasp, Mirage III, Harvard, Frelon, Albatross (Piaggio 166), Shackleton 1722. Also there was the "coelacanth Dakata" (which was the aircraft that brought the first coelacanth - a prehistoric fish) back to South Africa in 1938.
As well as the main museum at Swartkop, near Pretoria, there is also a nice branch of the SAAf Museum at Port Elizabeth where they have been restoring the ex RAF Museum Oxford which was exchanged for a Ventura.
It probably pays when visiting foreign countries to contact the museums before you travel.