Nice-sounding concert at St. Bart's, Westwood Hill, today at 5 pm - part of Vivaldi's Four Seasons, plus some Bach and Telemann, I think. I may go along. Do they do them often? Last time I looked at their website, they didn't have anything listed.
Edit: oops, it's been put up since then:
http://www.stbartschurchsydenham.org/whats-on.html