An interesting complex of tunnels and vaults are to be found close to the Roundhouse at Camden. The Camden Catacombs, as they have become known are were once owned by British Railways but have now passed into multiple ownership. Some sections were demolished during the redevelopment of the area while other sections belong to Camden Market who discourage access
This is a great setup waiting for a tarp to go over the top and sides, these get surprisingly warm with very little heat needed. Raised bed to get you off the ground and let the cold air drop below you and it puts you closer to the roof where there's more heat.
"A library in the middle of a community is a cross between an emergency exist, a life-rat and a festival. They are cathedrals of the mind; hospitals of the soul; theme parks of the imagination. On a cold rainy island, they are the only sheltered public spaces where you are not a consumer, but a citizen instead." Caitlin Moran in "The Book Habit"