Had some spare time so did some route planning.
White is a slightly extended commute to pick off two squares near work, will do that Thursday.
The rest are plans for Monday (day off) or weekend rides. Most are ~60km rides although there's always an option of extending to 80/100km if I feel like it.
Green would be next, starting at Whitton station and finishing at Hampton station. (Shorter route as I've got a funeral to go to on Monday). Hampton station has a slow service so will probably just cycle home, it's only another 15km.
Yellow is 60km starting and finishing at home. There's a bit of silliness to get a tile East of Claygate, plus a short bit of public footpath to get between Claygate and Chessington.
Blue is another 60km ride, starting at Ashtead and finishing at Stoneleigh. Wiggly route with a couple of turns just to cover tiles, I should probably just leave the 3 most Westerly ones for a better route that takes in some isolated tiles near White Down that I need. If I cut off ~10km of that nonsense I'd have time to ride all the way home.
Purple is a 45km ride (so I'll probably ride to the start at Epsom to bring it up to 65km). Lots of nonsense around Mogador to bag a relatively isolated tile (although I can drop in on The Sportsman pub for a drinks top up).
That would bring me up to 14x14 (the black square) with some SE London riding to move to 20x20 relatively easily.
For the SE I just need a Hilbert Curve route planner...