I am really intrigued by your find Kongetro! Thank you so much for sharing it with us.
I have only had time to look in one database so far, but I found one other reference. The concert, which was held on 31 May 1938 at the Park Lane Hotel in aid of the Red Triangle Boys' club, was patronised by HM, the Queen Mother over many years. Most of the news reports simply mentioned her presence.
This one from the
Sketch contained the description of the tiara, necklace and bracelet. Unfortunately, I could not find a photo of QEQM on this occasion.