In 1938 her husband succeeded to the earldom and she became known as Lady Beauchamp.
Later she was seen wearing a different tiara.
The Earls Beauchamp (family name Lygon) were wealthy, and the various Countesses wore some major jewels.
The title became extinct in 1980 but female members of the family remain.
Is the tiara worn by Lady Elmley in 1937 still extant? I don't know. It is possible. It is also possible that it was dismantled to make new jewels, or inherited by other members of the family. There is a relatively good amount of information on the family on the net.