I know a fab instuctor in Bucks who events and is the most fantastic jump trainer, also is an amazing dr rider, and his wife is a dr rider also - takes me 25mins to get there from J22 of M25 so not too far... Chris Haywood - google Deep Mill Farm.
there's someone in Herts that used to teach me, Tom something, I can't for the life of me remember his surname but he showjumps and deals horses aswell
i can recommend Annette Lewis, she teaches at Norton Heath, Brook Farm and Patchets, you can find her number on the BSJA website under accredited trainers.