Couldn't see this on your list here so thought i would add...

I'm going with the Vauxhall Owner's Network (my personal car is a VX)

Details of the event can be found here;

Castle Combe Circuit Performance Car Action Day

Might see some of you there, hopefully!

Don't suppose you happen to know what they mean with 'Track Package'?

When I went to this last year, it meant you get a show / stand type parking place and a 15 minute track session.

Hmm, sounds worse than Trax

Well I am up for it if I still have the Fabia by then.

If a club stand is booked, i think you can get discounted rates for track use/entry

well i know we do with the VxON...

IIRC, i ordered £40-odd worth of time in spetember, and ended up getting just over half back!