theleveller, it's the same here in Norfolk. Large groups cycling two or three abreast, or close together in a line, so that overtaking them is difficult. Also, with the many tight bends on our single-lane country roads, I worry about a motorist suddenly coming upon them and mowing them down.
In Norwich they often just go straight through red lights. I've never understood this, as it's so dangerous for them.

I do know London quite well, and agree that trying to drive there is much harder than either walking or using public transport. And I should imagine that finding parking for one's car is a nightmare!