Yes and no.
You've got to get there = £
Hourly rate for a 172 is about £65 wet. By the way, a 172 is often regarded as a 2 seater in SA because you'll be flying mainly at high altitudes.
Lanseria in Johannesburg are supposed to be good. Be aware that many places have a minimum daily charge equal to about 2-2.5 hours on any aircraft you hire from them. Fine if you fly occasionally but not for trips away from base. I gather there are other great places to train on the south coast, near George.
Licence Validation takes about 3 days. No problem really, provided you do it near Johannesburg, otherwise your application goes in the post and the SA postal service is pretty awful so it can take 10 days or more before you're ok to fly on your own.
Beautiful, friendly, cheap country. I'm going to do hour-building there. PM me if you want to know more.