Thanks again
I was in there today and was wondering why there was an external staircase leading from the changing room/shower area, which is on a mezzanine type first floor that covers just about an sixth of the gym ground floor area, but that's just a guess. the owner told me that it cost him 3 grand to put it in because it was insisted on by building control when the changing rooms went upstairs.
I did a few rough steps and the TD from the changing rooms,down the internal open stairs is approx 15 metres and then there is two way travel from there, well inside the 45 metres TD for two way
There's no auto detection, just fire alarm call points
I can only assume it was because someone could be in the shower at the time of a fire...but maybe I've been out of it far too long