Our group did this venue at the beginning of June. All I can say is what a place. The building is active from the top to bottom, with the longest drop fire mans pole in the world, gutted they wouldn't let me try it out, but we did find the kids one and got friction burns giving that one a go, LOL. The cells are great too, with some original stuff from one Charlie Peace the Victorian pick pocket and murderer. There is original stuff all over the building plus an actual fire mans uniform from 9/11 great stuff if you can get your hands on it for psychometry.
If you can get there, and it takes some finding in the Sheffield streets, the sat navs want to send you down what are now dead ends and pedestrian bits. Just look out for the revolving blue light on the top, it will help you to find it. No I am not joking on this it really has one. And if you can put up with snake pass, a nightmare to drive on especially in very thick mist in the morning, then, I can't recommend it highly enough.
Just to warn you though outside we were told it is a known red light district, and a few of our smokers got, shall we say propositioned a bit, lol.