Here is a link to some photos from Getty taken on 5 July 2019, so I assume these are the photos referred to in the article, as it says the Duchess was in Mayfair.

https://www.gettyimages.com.au/photos/duchess-of-york-july-2019?family=editorial&phrase=Duchess%20of%20York%20July%202019&sort=best#license

She is definitely wearing the necklace (and I presume the earrings) given to her by the Queen and the Duke of Edinburgh. I've no idea about her bracelet.

The Duchess has been seen wearing the demi parure several times since her divorce. Obviously they were a personal gift, rather than lent to the Duchess.