Here is the full photo
The ball was given by the Duchess of Sutherland, who was described in the press as wearing a high tiara and a brocade gown. Perhaps the lady is the Duchess but, if so, she is not wearing her famous art deco tiara. Every body who was any body attended this ball. Not only was it a coronation ball but it was the first time a King or Queen had attended a ball in a private house since 1914 --according to the press. The King and Queen and Queen Mary attended.
Some other photos of the Duchess from the same era.
1934 at Opening of Parliament