To validate your license you will need a student license number to write the law test, this takes time to get.
You can book for an online exam at an approved school or at the SACAA premises, 24 hour notice is required.
Under new regs, if you fail, there is a cool down period that gets longer the more often you fail.
All things take time to process so you need to plan in advance.
Most schools offer hire and fly but you will need to be legal and have a check ride and show you are competent in local airspace.
Most will require insurance for the deductable.
In that area there are plenty of options at Wonderboom, Grand Central and Lanseria.
Flying around the Highveld is world's apart from pottering around the UK and should be treated with respect else the runway or bush strip will smite thee.