LondonDerry Farm in Nutley is a lovely yard, fairly big in terms of a lot of liveries but very friendly. Excellent hacking direct into the Ashdown Forest.
Faircote stud as suggested above.... But there are three seperate yards there.... I would 'suggest' Equus Livery (Alex Chapman) above the other two
Did you find somewhere? A friend of mine has just contacted me to say they have two spaces in the Nutley area - PM me if you (or anyone else looking round this way) would like details.