At my high school every second maths teacher was South African. Didn't really like any of them either, the English and History South African teachers were much better blokes! This was palmy too, a sizeable number of pupils were also South African born for a provincial city. As far as I know, none of them have ever gone back to SA to live, though a few have moved to aussie as you'd expect. The only surprising thing is how few SA born cricketers have played for aussie, but I guess they produce enough home grown talent in that sport, unlike tennis with the eastern European women.
I actually think the reason those figures aren't higher is because South Africans take so many precautions already from what I've heard and read.