The trouble with Tripadvisor and the like is the info is usually by 3rd party contributors and often out of date! Always best to be guided by info from original sources.
Alternatively, ask on FB (I couldn’t, I’m not on FB, I just check it for information) - https://www.facebook.com/VisitNewMills
And there are some interesting illustrations on a local history related FB - https://www./262947845549867/
And the town council has a Contact Us tab, plus several PDFs about the heritage place being renovated or redeveloped:
https://www.newmillstowncouncil.gov.uk/