Writing/Critiquing Groups in London

In the hope that as is often the case lj knows the answer, does anyone have info on sf/fantasy writers' groups in London that are welcoming new members? (This is to help out someone who's asked to join CWIL in Cambridge but who will actually be living in London. [Tho' the person in question sounds so interesting I might want to keep them for us!])

If you don't want to post info in a comment, feel free to email via the lj email (I do check it!).

Many thanks.