You can fly on a validation but you cannot add any rating s to a validation. I.e if your JAA PPL doesnt include night then you will not be able to fly night there.
If on the other hand you get an SA medical sit the very easy PPL exams and get a SA Student licence and then do the SA PPL skill test. You are exempted all the training as your JAR PPL counts as a contracting ICAO PPL and then you get an SA PPL.
You have flown the same test and can now add ratings such as night IR etc if you wish whilst you hours build which will enable you to convert your IR (for instance) when you return only having to do 15 hrs in UK rather than 55hr IR. Good eh.
As for where to go go anywhere except FTC unless you really really really want to fight every day for every aircraft and pay for your own fuel, get yourself out of any trouble and possibly risk your life.
Good luck.
VT