Have you tried contacting them directly to remove any offending articles? Other than that, you can try to contact the host provider directly by filing a DMCA cease and desist. But, the UK process to a DMCA Takedown is a bit different than in the US - found this article on Quora that may help you guys:

"Copyright Law: Is there a UK equivalent of filing a DMCA cease and desist for websites hosting copied content?"

http://www.quora.com/Copyright-Law/Is-there-a-UK-equivalent-...