I keep a web page of all the 10 SA approved AMEs I know of in the UK - places like Gatwick, Kent, Central London, Bishops Stortford, Somerset, Glasgow and Hampshire.
PM me for the details, not sure if I'm allowed to put the link up directly!
ps: if you visit one for a SA PPL medical, please make sure:
1- They tick 'Class 2' not '3'
2- They fully sign against any alteration they make on it!
I've had a few cases of processing SA PPL renewals where I've had to ask for a new or re-signed certificate, for one of those two reasons.