Make sure you check you're eligible to join; it's one of these places where you have to have a membership, normally based on being a soletrader of some kind. However, they will let you go and look around. It costs something like 20quid a year and I think it is worth it. They also have tyre fitting garages which offer Michelin tyres at incredible prices and the fitting service is better than any I have come across; the wheel balance is perfect and they take real care of your allows.
They also have loads of other stuff from food to books to electricals and the quality is good even if the prices are cut down.