I think starting yet another group or club is not a good idea. There is probably a larger density of clubs already on the west of London than anywhere else in the world. (I think I pass about 7 on my way to work) This attitude of splitting into single subject groups is overall harmful to the hobby as it puts up costs and makes cross fertilisation of ideas and skills difficult.
Why not go to your nearest club's committee and explain your views. It will probably turn out that quite a lot of people are intereseted , just not obsessed, will be supportive if given the right opportunity. It would be less work to set up a special interest subsection of an existing club than start a new complete club but don't expect them to drop all their personal activities and do the work for you.
Edit : looks like you are already doing that.
Edited By Bazyle on 05/01/2014 14:39:09