As a parent of 3 kids I've yet to see why the need for private education? My eldest lives in Natal and we are in Western Cape and two of my school going children both go to public schools.
Reality is we don't have an extra R10K per month to waste on bragging rights, there are still many public schools who outperform the majority of private schools. I live in an area where the 2nd, 3rd and 4th best schools are all public, quiet an achievement with the number of quality private schools in our area.
I question netting R40k as being enough for private education, more like > R60K and plus R10K for every extra child.