Here is a better view of the Tiara worn by Lady Charlotte, at her Wedding to the Duke of Noto, HERE! I initially thought it might have been a Tiara from Bentley & Skinner, but the design is different, so it is likely from her family!

The Duchess of Calabria wore a historic set of diamond buttons, which are usually worn as a Tiara, and it was revealed to DavidR by a member of the family that they originally belonged to Archduchess Maria Cristina, Duchess of Teschen.