http://www.aerospace-medicine-sa.co.za/ - This doc does all the medicals.
Bear in mind you will still have to travel home every year to get your LPC done if you are on a validation, and then apply for a re-validation each year. Is alot cheaper to get the local ATPL and not use your JAR at all.
Get your employer to apply for the work permit for you, they have to fill most of it in anyway.