I've got some connections in the track day area (I run Vauxhalls VRX days) and the best bet is to block book an existing day from another operator. Castle Combe for example cost £4500 to rent plus you need PL insurance, marshalls the costs soon rack up.
Operators I'd recommend include Bookatrack, Easytrack, Goldtrack, RMA. The cheapest tend to be BaT and EzT.
I'm happy to help organise something but remember weekends are more expensive than weekday and circuits are impossible to get in summer because they're busy with racing.
Good airfields (goos for beginners as less to hit) include Elvington, Hullavington (Swindon), Brintingthorpe and Bedford.
Best thing is to put up a list of dates/places and agree on which one to go for.