Were you able to get the plan to confirm that 204a Coldharbour Lane is the whole site - and that the Celestials own all of it, not just the building visible directly looking down the alley from the street? (
See Editor's last pic)
If so maybe someone should ask them if they mind photos being taken inside & out?
Presumably if it has been used as a factory and a social club there might not be many "original features" left. But you never know.
I admire everybody's diligence on this thread - and I am grateful you are sharing the knowledge.