I used to work at Tool and Steel products in the early 80's, the building was a single story with a long flat roof which you access from a flight of stairs near the storeroom.
You could walk accross the flat roof to gain access to the entrance on woodseats road, where the roller shutter doors were.
I've never had this confirmed but the story was that the building used to be 2 floors and was bombed during the war.
I remember the building well it was a dark eerie place at the best of times and also remember it flooding a few times as well.
Some of the stories about seeing a ghost of some one on the stair
landing washing their hands and also footsteps on the roof when no was around, I remember well.
Not sure if this is any help, as far as I can remember there wasn't any buildings where the business park is located.