Which brings me to the second point - which is to ask whether Wikimedia UK could support such locally-based activities by, for example, hosting a mailing list, wiki, and/or other webspace? It seems to me to be well within WMUK's remit - but I'd like to hear what other people on this list think.
It's certainly within the chapter's remit, but probably not within our capabilities. At the moment we're looking to get hosting on WMF servers, so we can't offer anyone else hosting. Come back in a year and things may have reached a point where we can help. If there's anything else the chapter can do, though, please ask - I think it's a fabulous idea and is definitely something the chapter should support.