The Consumer Action Group hosts a 'buddy system'.
This is a system whereby a user of the forum can enter their postcode and a list will be provided of people that have either gone through the process of claiming their charges back, or are willing to attend court with you for moral support.
The system uses 'as the crow flies' as a way of determining how far a 'buddy' lives from you.
The system firstly converts all the postcodes in the UK into a metric grid reference, and then uses pythagorus to determin distance. On the whole the approximations are farily accurate.
The buddy system can be found here: http://www.consumeractiongroup.co.uk/buddy.php