I guess whats written in law and what is enforced, seems to be very different. Seriously, I live in Merton and go to Wandsworth a lot and Ive often parked on the pavements and like I said, as long as you are not obstructing the pathway, you are free and clear. In Merton you see lots of bikes parked on the pavements and locked to the lampposts. As long as you dont do it in the main high streets, seems ok. Thats my experience in 12 years anyway.