I recently bought a horse from emma at clipclop traders and can say that he is everything she described and more. He is also very honest and a lot of fun (my trainer agrees). Emma is very nice and tells it straight. Good luck, PM me if you want any more info.
If you are tempted to go to Kent (Maidstone area) I have just taken a dealer to court and won so obviously wouldn't recommend them. Pm for more details.
I brought my guy from Equine Agents and yes thery are all on the "slim"side but soon beef up. Most come over from Ireland so have that journey then in the nicest way are at a dealers so not maybe feed the best quality food. But they are all good horses and what you see is what you get.
Another vote for Emma at Clip Clop Traders - very smart riding club horses and good person to deal with. Good local reputation unlike some others based in East Sussex.