The YMCA took over the premises of the Grand Sultan Divan in Needless Alley sometime in the late 1800's I think without checking my notes. The following isfrom an article in Showells Directory about it. My gt.grandfather's sister was working as a nursemaid to the Owner of the "Dancing Saloon" of ill repute in 1871. See the thread on Sultan Divan.
...when the notorious "Sultan Divan" was closed in Needless Alley, it was taken for the purposes of this institution, the most appropriate change of tenancy that could possibly be desired, the attractions of the glaring dancing-rooms and low-lived racket giving place to comfortable reading-rooms, a cosy library, and healthy amusements. Young men of all creeds may here find a welcome, and strangers to the town will meet friends to guide them in choice of companions, or in securing comfortable homes....