There's a detailed article in the Times of Oct 26, 1934. I can;t save a copy to send you, but it marks the occasion of the move of the club to the Halkin St premises with some history. Established in 1894 as a London house for county ladies, it was a brave undertaking in its day, when it was shocking for ladies to have a house of their own and receive men friends and guests. The Halkin St operation was in the house built by Mr Hugh and Lady Mary Morrison 20 yrs earlier on the site of the old Belgrave Chapel. The description mentions 30 bedrooms with running water, some suites, marble halls, telephones and so forth. The Club President was Queen Amelie of Portugal. it was a non political club, with some high ranking members of the honorary committee (duchesses, countesses, Ladies etc)
from the level they were aiming at, I suspect your mother worked in the club and possibly lived in?