Hi danmont,
I live in Witney... I would recommend Bristol Harbourside for the next APAT regional. Me and a mate will be going, it should be all "dealer dealt" (the first one was). It"s a nice room and for us it"s closer the The Vic and Luton, although from Oxford there wouldn"t much in it.
Aside from APAT, there are regular tournaments at the [Stanley] Reading Sporting Club, not sure of their schedule... quite a few people from Oxford travel there.