Take a look at SAFTA south of Johannesburg. (
South African Flight Training Academy - Residential flight training) They're right next to the GF and literally have the airfield to themselves. You'll get far more time training than sitting waiting 15 minutes for take off clearance and another 15 minutes getting to the GF like most other schools.
They also have an ex B747 airline training captain as their CFI and a former Air Force fighter pilot as their CGI. One of their owners is a former US Army National Guard helicopter pilot and a current SAA airline pilot.
They offer inexpensive rates and quality accommodation and meals. Plus they use the C172 as their primary trainer where most schools use the smaller C152. Email them for info!!