I live Near Brentwood and I am in Glendene CC which is probably too out in the sticks for you. ( Rides start in Blackmore) I dont know your experience but its not really a club for beginers, if you like a race to the cafe or the last few miles home it may be for you . Winter rides are usually 18-19mph average summers can be over 20mph. Quite a lot of my fellow Commuters are in Hornchurch CC, all the ones I know are very friendly and decent considerate but fairly fast people. looking at Strava on some of the guys I know, they go like a bat out of hell sometimes ( 20mph + average rides in the summer) . One bloke I know in HCC has 11 pages of KOMS. I dont know if they do a slower group, if that is your thing I can ask. Heard a lot of good things about Essex roads especially for beginers with rides for all abilities but I thought they would be too far out for you. Redbridge I run into the odd one or 2 but know nothing of their rides. Crest a few years ago was a smallish club with dedicated racers only in it , the couple of people I know in the club are very fast ( for their age) I believe the club has got bigger so dont know what its like now.