LTNMAN; you are correct about the hangar, it was built for London Aviation Centre and the company was owned by a couple of brothers, can't remember their names at the mo, but they were going to " take over aviation " as we know it !!
As far as I recollect, it was built to that size and not with a view to enlarge it. There have been a couple of companies in the offices down either side, one I seem to recall brought over used Mooneys from the states and then sold them on. Also there were times the odd aircraft was hangered there and of coarse it did have aircraft in it when London Aviation Centre organised the aircraft auction at the premises.
I am fairly sure I have also seen helicopters in the hangar at some point ( besides the police one that is ).