Thanks for the suggestions! After about more research we're pretty sure it wasn't an Anderson shelter or Nissen hut based on the size and footprint - neither would work with the curved corner on the right and based on Wikipedia the wall lengths are all wrong.
Happy to hear you agree about the...
Looking for any suggestions on when and why someone would have built a cement and corrugated asbestos structure in the garden of a 1930s property in SE London. Nothing on planning permission and pretty sure it's 1980s or earlier.
See drawing!
- 2 parallel walls of roughly 4.2m and 2.1m length...