Art Nouveau Silver bracelet set with Mother of Pearl and Amethysts

Outstanding Art Nouveau Silver Bangle.  Silver finely worked with Detailed Ivory Leaves and sinuous tendrils around bangle body; single leaf to the Amethyst Cabochons and two leaves one above the other, surrounding the Mother Of Pearl Cabochon. Very old bangle and Hallmark intact but slightly rubbed, appears as  PB  followed by  925  within a lozenge, followed by  possibly a Lions Head? And another mark after, possibly British mark. Dimensions approx.: wrist elliptical opening 6.5cm wide x 5.3cm; gap at rear 2.8cm, adjustable as bracelet flexible; width 2.4cm; Silver 1mm+ generally.