Antique painting on metal Duchess of Devonshire Princess Diana silver gilt frame

A beautiful small antique 19th century oil painting after Joshua Reynolds, depicting Georgiana duchess of Devonshire one of princess Diana's ancestors.  Under glass framed within a silver gilt filigree frame set with pearls, not marked but tested as high grade silver. Some losses to frame and two missing pearls, gilded patination worn away to the silver in places, all commensurate with age otherwise in very good all original condition.  Measuring (whole frame) 19 cm x 15 cm approx