Hi Jan and Fred,
When we were in Cape Town in September, we used Wayne Milne, the owner of Take 2 Tours. He was great and worked out a full day tour that accommodated our specific interests.
http://www.take2tours.co.za/ We also considered Selwyn Davidowitz since he gets so many positive reviews at the Fodor's message board.
http://www.ilovecapetown.com/ Have fun in South Africa! Len and I wish we were going back right away!
Andrea