I went today soon after opening time out of curiosity as the first Friday of every month is open to all genders, couples and singles. I was welcomed warmly, given a towel, paid £18 + £1 for a locker then, wearing only the towel, explored the dimly lit place along with other men doing the same thing. The nearest I saw to a member of the opposite sex was a man in drag! Before I left, another man told me that women tend to arrive later in the day. But I was not free to stay any longer.
Without divulging too much, as a lad, I knew this building when it was the research department of ICI Alkali Division!