We have a UK-based mailing list, wikimediauk-l, for Wikimedia-related
topics concerning the UK. It was set up as a discussion list for the
prospective Wikimedia UK organisation. I often post UK-related article
discussion, media stuff, etc. to it.
There appear to be a lot of UK-based readers of these lists who aren't
on it and probably should be.
List page:
http://mail.wikipedia.org/mailman/listinfo/wikimediauk-l
WMUK:
http://meta.wikimedia.org/wiki/Wikimedia_UK