There is a limit to the number of show car spaces so if you're interested best move fast. Its cheap too for display cars - just a fiver for two people & their car.
You can contact the museum and ask them to send you an application form or I have one scanned in so PM me and I'll e-mail it over to you. You have to give your car details, etc & send the fiver (old skool cheque!) and a SAE to 'Whitewebbs' so they can post the tickets back to you.
Here is the flyer:

