Spot on and good detectiving.
I did some browsing to give some history when it was guessed, but there is not much on the internet.
It is called Hare Street Hall, and is currently 4 leasehold flats internally. Hare Street ran in front of it where the car park now is, but is not annotated on modern maps.
The Bethel religion seems to have several different sects and groups with such a name, so I cannot reference anything too specific about that either. The various groups are globally located, not just in the UK.