Thank you very much, Maridje, Baxter, Mauriz, Annie and Beth, for these fantastic pictures. Lady Sarah Chatto has indeed worn a lot of her mother's jewellery, and with much elegance!
Regarding the pearl and diamond star brooch worn by Lady Sarah Chatto, it is an heirloom from Princess Margaret, not from the Countess of Rosse:
Direct link to Getty pictures: http://www.gettyimages.fr/detail/photo-d'actualité/princess-margaret-at-st-margarets-church-westminster-photo-dactualité/52107313 Caption: LONDON, UNITED KINGDOM - MAY 16, 2000: Princess Margaret at St Margaret's Church, Westminster, for a service of thanksgiving for the life of Lord Charteris of Amisfield, former Private Secretary & Lord-in-waiting to The Queen. (Photo by Tim Graham/Getty Images)
Caption: Sarah Chatto leaves Canongate Kirk on the afternoon of the wedding of Mike Tindall and Zara Philips on July 30, 2011 in Edinburgh, Scotland. The Queen's granddaughter Zara Phillips will marry England rugby player Mike Tindall today at Canongate Kirk. Many royals are expected to attend including the Duke and Duchess of Cambridge. (July 29, 2011 - Source: Chris Jackson PT/Getty Images Europe, via Zimbio.com)