Hi Dave, Yes most of the best Parking in London is free on the weekends.
Different story in the centre which is too full of tourists.
There is always a yellow line, but it states on the past something such as "Permit Holders only 8am to 6pm Mon-Fri"
I was at 51.487177, -0.008714
Saunders Ness Road, its right beside a little park where there is the start of the foot tunnel over to Greenwich. Well worth a visit.
Another favourite of mine is 51.536513, -0.050563
Gore Rd, it runs alongside Victoria Park, great place to take the kids or to go roller bladeing.
From there you can walk along the (or cycle but busy) the Canal through,
Broadway Market (Great on Saturdays)
Islington,
Then over the top down to Kings Cross,
Along to Camden Market, (Punks & Goths)
Regents park past the zoo
Over to Paddington Basin.
Always something different to see.
Please leave me a space when you all go there though.