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A great many more results in google for "sports memorabilia" it seems. A massive area in the states. Not sure if it's so big here, but I certainly wouldn't say that they overpaid for the name. Had a peep at sportsmemorabilia.com and it looks pretty impressive. Looking at some of the prices for signed items here: http://www.spiritofsport.co.uk/ suggests that it might be a bit of a bargain.
Have some knowledge of the market and would also agree that 'sports memorabilia' is the correct term. It's quite a good niche area for the UK, but if I wanted to build a brand up selling the items I would definitely prefer to use American.co.uk which sold on DL not long ago for less.