You may also be able to take the matter to the OEA and see if the Ombudsman can't help out. Google OEA, they're part of the OFT, and you can ask for help through the website. If the contract is very unfair, you may be able to get the charges reduced.

The OFT is taking Foxtons to court over unfair contracts towards Landlords; I think you may have a chance with arguing for tenants!