Just a quick follow up note. I've tried a couple of different routes now. I came home on Friday night via Westminster, then Boris' CS8 route all the way to Wandsworth - then out the A3 to Kingston Hill. This was an ok cycle - Boris's blue route was very good - but Wandsworth to Kingston Hill wasn't too pleasant and it is a longer route (took 10 minutes more that the Kings Road option though there was a strong head wind). I have also tried A3 from Kingston Hill to the top of Putney High Road rather than going through Richmond Park. I quite like this route - it's shorter and quicker than the Richmond park route - but not a scenic. I'm going to stick to this route going forward - and save the Richmond Park route for days when I'm not in a hurry...