I have to agree that I have never seen such films available in Premier Inns or Travelodge, or at Warners Hotel (which are only for adults)
I did not have to search for them, inorder to get into the normal TV channels you had to go via a menu, one of the options was for Adult Films. I did. out of curiosity, click on that, it was then that I was shocked by the very explicit descriptions on the films on offer, at that point I went back to BBC1.
I have to say that the hotel, which was not in London, was of an outstanding standard, as good as any I have stayed in Worldwide, and I have stayed in an awful lot (many of which have been awful)