studentpilotmcuk,
I really do sympathise with your post, especially if you have nothing to hide or are not breaking the law.
This is just a thought and i'm not sure how it would work, but if you popped along to your nearest airport police station with a copy of your passport/ID and also details of your vehicle and let them know where and when you will be spotting, and then if you are pulled up by any jobsworth security guard you could inform them that you have already informed the police of your presence. Would this work? just a thought.
Iain