I agree, Mollie - I didn't explain the full story about having been before, mainly because the whole story would have gone on for a very long time. I should have done in order to put it into perspective.
I was particularly surprised about the immigration in Cape Town, especially as the immigration in OR Tambo were really friendly and welcoming. I even keep in touch with a woman who works there, as well as a number of other people in Joburg, so I didn't mean to put down SA and it's people as a whole. And to be honest I had a few minorly disappointing experiences the first time, when I was there for over two weeks (such as giving a little girl I was particularly close to our brand new camera and then the mother selling it to go to the casino - and I was not upset because of the camera itself, but because the little girl was crying that her mother had pawned it). But all in all the experience was positive, unlike this last time.
As for the race issue, I think anyone who knows SA reasonably well will concede that this problem still persists. I am mixed-race myself and people from all backgrounds in SA are, as a whole, not used to that concept. Therefore it arouses curiosity, particularly among the older generations, which can be tiresome. However I accepted a few comments about that the previous time, and have tried to be understanding about it. But it does get irksome after a while.
I'm pleased you had a great time and hope you do again. I don't want to put people off SA completely and didn't want to sound overly whiny or negative, so apologies if people have misconstrued that. I think the mugging was the straw that broke the camel's back, although as I said in the OP, that could have happened anywhere, to be fair.