The relevant section of AB would probably be 'Hobbies & Interests', under 'Society & Culture'. (Hint: To see all of the sub-categories offered by AB, click on 'Topics', at the top left of your screen).
Any local auctioneer will be able to give you a free valuation of your items but it might be best to contact a specialist firm. The owner of the 'Old Classic Car' website might well know of a firm which deals in motoring memorabilia. He welcomes mail and can be contacted at this address:
dodgenut @ 4onthefloor.co.uk
http://www.oldclassiccar.co.uk/classic_car_art icle8.htm
Chris