How about helping to form the new oxfam group? That way you can help forge the way a group functions instead of joining one that is quite set in it's ways and that doesn't quite suit you as a person. I just saw there is an Oxfam speaker event, with free wine (crucially) next week. Maybe that will be more your perticular brand of tea. I know they are looking for new members to join the group, and it could be fun.