Folks,
As one who learnt with Moray Flying Club based at Kinloss, there's a few things to pass on reflecting some of the comments above...
Quite a few airfield have VGS flying at the weekend. While this does mean that Avgas is available it also means that the circuit can be busy.
Well worth calling and asking if there are any PPL's based there who are known to ATC. Theses guys are a good source of local advice and information. Even better if there is a Flying Club there, as you may be able to 'visit' them and receive assistance.
Circuits shape and size can be varied for different traffic types. You really need to be aware of these, and of the local procedures wich may not be as 'standard'. The comment about local VRP's is quite correct.
Even more than usual, be prepared for the unexpected! Foreign fast-jet formations can keep ATC quite busy and you may not be top priority if faced with 8 German Mig29's or 14 F-4's or a few Spanish Sea Harriers arriving within 10 minutes. These guys will also be using the visiting aircraft facilities.
At weekends you may not be welcome at all - some airfields will be closed for sure.
With all that in mind, however, I'm quite sure a polite, confident and competent PPL would be well received and be given appropriate service and hospitality from the military. It is fun, after all......
More to come if I think of it.
Bear555