Prunie
I just got back from doing the same. Before going I posted on the African Aviation forum and got some v. helpful replies - if you visit it and set it to view more than about 15 days back you'll find "SA questions from a UK PPL".
Getting a license conversion is more tedious than the US - I went with a safety pilot instead, partly because of lack of time and also they are in the rainy season and the weather was unreliable, so no guarantee of flying.
We flew (legally) over the centre of Pretoria low level - unusual experience for a UK pilot, and it goes without saying that the views there and across the country were stunning.
As for paragliding - I can't help but think of Table Mountain!!
By the way if you go to Cape Town the tourist trip to Robben Island is a must.
Have fun
Garry