The tiara as seen in the photo Dave provided a link for



has been identified by Ursula as the bandeau given to her by Edward VII and Alexandra as a wedding gift in 1866 https://royal-magazin.de/england/helena-princess-christian/helena-diamond-tiara.htm

Perhaps I have misunderstood what was said; however, I feel that only the base section of the tiara would have constituted the bandeau.

Certainly Princess Helena (Christian) used this base to make different tiaras.

Here with stars


Here with a pearl enhancement/superstructure, which may have doubled as a necklace.



I suspect that the superstructure in the first photo may have been a pearl and diamond bracelet.

Princess Helena Victoria was photographed wearing the bandeau for the Devonshire House Ball






I have never been able to make a decision as to whether she was wearing the bandeau to the ballet in 1934 --the photo is too blurry to say.