It's an interesting place to have Elinor meet up with Robert and her brother. Mr. Gray's shop at No. 41 Sackville Street was a real place.
As we have in the thread below, Robert was there indulging himself in something utterly frivolous. John was there to buy something for Fanny, but made sure to emphasize his poverty so he would have no compunction to buy his sisters a pair of earrings or anything!
Elinor, on the other hand, was there "carrying on a negociation for the exchange of a few old-fashioned jewels of her mother". It's almost a throwaway line, but don't you wonder if she was exchanging some jewelry her mother had, perhaps as a gift from their father, for some money, at her mother's request?
Mr. Gray, the proprietor, did some work for the royal family, creating some Order of the Garter pins that cost upwards for £ 400 each. In the late 1780s, the Prince Regent spent more than £ 20,000 in the shop in three years.
Even though there was really a Mr. Gray, I've sometimes wondered if the name "Grey" was a deliberate choice for Sophia, meant to evoke the idea of expensive items for sale in the jewelry shop...