@TMangnall
It's an old paper mill, these are the beater machines that break up fibers between the pulping and rolling stages of the process. Some more photos attached. I had to be careful as security had drilled holes in so they could see inside, so I didn't stand out in the open in this area for long!
I have a whole album and long article, which goes into both the history and the paper making process in general - https://www.obsidianurbexphotography.com/industrial/robert-fletcher-sons-paper-mill-england/