I guess that the golden cross is positioned this way in order to prevent it from dangling too much and hurting the Duchess (or damaging the cross itself) when she lays her hands onto a table, or such similar movement.
The charms bracelets are a very common type of "sentimental" jewels in the British Royal Family. Besides grand dazzling jewels, 19th or early 20th century jewellery had a lot of more modest, sentimental jewels, expressing affection and love to one's spouse, parents, children, or memory of the trespassed ones...
The Royal Collection's website records several similar charms bracelets:
Queen Victoria's Charm Bracelet:
http://www.royalcollection.org.uk/collection/65290/queen-victorias-charm-bracelet Creation Date: nineteenth century Materials: Gold, enamel, diamond, photograph Dimensions: 10.3 x 2.2 cm RCIN 65290 Provenance: This bracelet was worn constantly by Queen Victoria. This was one of a group of jewels placed in the ‘Albert Room’ at Windsor Castle after the Queen's death in 1901. This was the room in which Prince Albert had died in 1861 and the Queen left instructions for a specific list of personal jewellery to be placed there and not passed on in the family. Description: A gold charm bracelet with sixteen various oval and heart shaped lockets, enamelled in black on gold. Some set with jewels, others engraved, several with inscriptions. Miniature photograph of male head.
Charm bracelet:
http://www.royalcollection.org.uk/collection/65275/charm-bracelet Dimensions: 9.0 x 2.2 x 1.3 cm RCIN 65275 Description: A gold plain link chain bracelet with six charms suspended from it. Three heart-shaped charms, one oval locket, one circular locket and one spherical locket set with cabochon red gem stones.
Bracelet with nine lockets, one with a miniature of the left eye of Charlotte, Princess of Wales (1796-1817):
http://www.royalcollection.org.uk/collection/10919/bracelet-with-nine-lockets-one-with-a-miniature-of-the-left-eye-of-charlotte Creator: British School, 19th century (artist) Creation Date: early nineteenth century Materials: Watercolour on ivory framed in a gold locket with serpentine border mounted with diamonds and a ruby Dimensions: 20.0 x 3.9 x 1.7 cm RCIN 10919 Reference(s): Vic Min 961 Acquirer: Queen Mary, consort of King George V, King of the United Kingdom (1867-1953), when Queen Consort (1910-36) Provenance: Bracelet and miniature first recorded in the possession of Mary, Duchess of Gloucester; bequeathed by her to Augusta, Duchess of Cambridge; thence to Queen Mary Description: A silver gilt flexible bracelet from which hang nine lockets; five are heart shaped, three circular and one oval. Six contain hair, two are empty and the last contains miniature of a left eye, blue, female, with light brown curls around it, traditionally identified as that of Princess Charlotte of Wales (1796-1817), framed by a diamond ouroubos border. The identification of the eye as that of Princess Charlotte of Wales is substantiated by reference to miniatures of her of this type such as that by Charlotte Jones (421459; Royal Collection; see also 422239).
Queen Victoria's Bracelet:
http://www.royalcollection.org.uk/collection/65293/bracelet Creation Date: 1840 - 1857 Materials: Gold, enamel, hair Dimensions: 11.0 x 2.0 cm RCIN 65293 Acquirer: Prince Albert, consort of Queen Victoria, Queen of the United Kingdom (1819-61), when Prince Albert, consort of Victoria, Queen of the United Kingdom (1840-57) Provenance: Given to Queen Victoria by Prince Albert, 24 November 1840. This was one of a group of jewels placed in the ‘Albert Room’ at Windsor Castle after the Queen's death in 1901. This was the room in which Prince Albert had died in 1861 and the Queen left instructions for a specific list of personal jewellery to be placed there and not passed on in the family. Description: Gold chain bracelet with nine enamelled heart shaped lockets of different colours; containing the hair of Queen Victoria's children. This simple chain and locket bracelet is typical of the sentimental items Prince Albert gave to the Queen. The inscription on the clasp states that it was given to her three days after the birth of their first child, Victoria, The Princess Royal. A locket was added for each subsequent birth, each one containing a lock of the child's hair and inscribed with the name and date of birth (text from Victoria & Albert: Art & Love). The hearts record the birth of the children as follows: pink for Princess Victoria, turquoise blue for Albert, red for Princess Alice, dark blue for Alfred, translucent white for Helena, dark green for Louise, mid blue for Arthur, opaque white for Leopold and light green for Beatrice.
I do not remember of pictures of Queen-Mother Elizabeth or Queen Elizabeth II ever wearing such charm bracelets. Not sure for Queen Alexandra and Queen Mary.
Diana, Princess of Wales, also owned a charm bracelet. Hanging from it were, among other charms, two capital letters for her sons, W(illiam) and H(arry), as well as a small golden wombat (the affectionate nickname given to William during the official visit of the Prince and Princess of Wales to Australia in 1983):