BG ! - sorry Lois, even when I was a young man, before the civil war - I was never a very beautiful boy. I had to rely upon my smile and my twinkling eyes. Now as a very Old Man I have to rely on my wits.
Re Pony Club,
I have never heard of the Wheal Buller RS down in Cornwall. It looks like fun but I know nothing about them. Cornwall is a long way for you to travel.
Lois, the idea of exchange visits with English kids is a good one.
All of the major English riding clubs have a junior section and they run for the young people 'pony club holidays' in the summer months. But you would have to have your own horse or pony.
As I suggested contact the BHS (British Horse Society) by internet and ask for a list of BHS registered riding clubs - especially those located in Kent, Sussex, Hampshire and Surrey. You will want to be close by Dover or Portsmouth - the major ferry terminals. Then make contact by email to the pony club secretary and ask when their horse holidays are. Then all you will need is a tent - unless you have a very expensive horse box which has its own bed.
There are now only a few regulations regarding horses entering England from France but you need to ask of a shipping agency in France - they will know the regulations. For sure you will need a horse passport and a veterinary certificate as a minimum. I suspect with the minimum of formality, you could deliver your own horse by horse box or horse trailer to England. But your Dad will have to drive on the wrong side of the road.
On my other post I mentioned the Passmore family in Llanthony. They went to the Grey Coat School in Horsham, West Sussex ( not too far from Dover) which I believe has a school riding club.
Contact Llanthony RC as I suggested and ask to speak with Briony - she will be able to help you. I suspect she might even speak some French.
Best of luck