P W Pilot,
You can fly in the UK or any member country of JAA with any ICAO PPL BUT day VFR only AND the aircraft has to be registered in the country you fly AND you must stay within the countries borders.
There are plenty of good schools in SA, you'll find websites listed under the ICAO website. Do a search for ICAO PPL's in SA. Lots cheaper than 43 but 43 are a good school all the same.