My guess would be no one sells them. I have certainly not seen or heard of anybody using them in UK and if it comes through anyone it would be the agent for other sports who would know.
Are this black knights racket good? Sorry to ask. I have not seen one here at my place before. Any photos?
http://www.blackknightuk.co.uk/products1 Is this the right company? Searching on google brings up a few results.