Never used CDWOW so I can't comment on the prices (I suppose I could go and look but I am too lazy). However I feel that £9.99 for a new CD from my local independant is a far better way to buy the CD than over the net. I get it that moment, can take it back if I don't like it and I can chat to the owner about what to buy if I go in with no idea. Not only that but it keeps trade in the country and the little businesses running.
I personally have no problem with them being fined. They are breaking the law and that is that. As pointed out other retailers offer good prices without importing why can't they? All supermarkets have cheap CD's (although only a few pence than my aforemention independant).