Just signed up for the 150-mile (what am I thinking?!) route of this. Starts and finishes at Stratford Racecourse, and looks like it's going to be a lot of fun. 30, 64 and 100 mile routes also available.
http://www.cyclistsfc.org.uk/events/cfcsportive/
http://www.cyclistsfc.org.uk/events/cfcsportive/