Regarding values, all I can tell you is that there is no reliable Maiden price guide or such a thing. An item is always worth what someone is willing to pay for it. I would say that 20 quid is a real bargain and that if you put it up on Ebay for instance, you'd get a lot more than that if you're lucky. But whether it's 50, 100 or 500 pounds depends purely on how big the fanatics are that will find it.