I did my cbt on a ybr, had the same problem... funnily enough it was about 2 months newer than the one I've got sitting in my garage (registered Feb 07) but that doesn't seem to have any problems. Saying that, I cbt'd 2 days ago and went on a nice long bimble yesterday for 50 miles or so - I'm in cambridge so it was a little busy in the middle of town on a saturday, so I went and explored the fens!
i'm going down to london next week to visit a mate, what's driving like there? busy, obviously, but do you just have to keep sharp to avoid people?
Gary