Don't know,might be worth having a look at the Ramblers site - www.ramblers.org.uk
Before you roll your eyes in horror, they've started doing youn people's walking groups as well as standard issue Rambler clubs.
The YHA site still lists the Hounslow group with a contact number btw:
http://www.yha.org.uk/sctn_abou/pop_up_localgroup.html
