My son (20) is an experienced horse rider here in the UK and wants to
combine world travel with working with horses (not just horse riding).
Ideally he would like to work towards an internationally recognised
qualification.
Any help & suggestions would be appreciated especially information on
international riding organisations and individual, reputable contacts
within the countries listed above.

In Mooi River, South Africa is a world renowned horse stud called
Summerhill. Mooi river is +- 150 kilometers from Durban on the main
highway to Johannesburg. Mooi river is the coldest place on the planet
in winters(well, I thought so) but the Spring / Summer time is
spectacular. Remember our Spring starts in September so send the boy
soon.

I don't have an address unfortunately, but the administration
telephone number is +27 33 263 1081.

About ten years ago I met a fellow that worked there as a horse
training assistant on a part-time basis. Perhaps they still do that
sort of thing these days. Give them a try.