Susy Dyson, the British-Peruvian model who was a fixture of 1970s jet-set social circles, is a firm believer in letting things go. “When you put things for sale, things start to happen, you see,” she said during a recent phone call from Peru, where she now lives. “Energy moves.”

Which is why she was not especially sentimental about the July 12 auction of some of her accessories at the British auction house Dreweatts. “Because I’ve let go of everything,” Ms. Dyson said. “I don’t wear anything at all.”

Among the collection of colorful ’80s Cartier bangles and pieces by the French master jeweler René Boivin was a striking watch featuring a champagne dial and an old-cut diamond and sapphire-set bezel, created by Mellerio dits Meller, the French jewelry house founded in 1515. It sold for 3,800 pounds ($4,980).

The watch, Ms. Dyson said, once belonged to the mother of her companion Frédéric Chandon de Briailles, who at one time was chairman of the Moët-Hennessy group, which is now part of LVMH Moët Hennessy Louis Vuitton. She recalled that they had met when she was 18 or 19 and working as a model and a cook at the Swiss ski resort Klosters. During her career, Ms. Dyson appeared in American and French Vogue and modeled for the likes of Yves Saint Laurent and Fendi.

“It was one of the first things he gave me,” Ms. Dyson, 72, said, adding that she put it on immediately.

“And so I wore it for quite a long time,” she said, but recalled later thinking, “I better keep it because you know might get lost or something.” So she put it away in her jewelry box, she said. “And there it sat for many years.”

The box, a Louis Vuitton monogrammed case that was Lot 255 in the auction, ended up with her sister in England; her nephew rediscovered it while tidying the house during the pandemic.

“I thought, ‘Oh look, I’ve got all this stuff sitting there, it’s in England, which makes it easier to sell’,” Ms. Dyson said. “And I just got cracking.” She was spurred by a recent successful sale of two personal portraits, photographed by Helmut Newton.

This spring the jewelry box and its contents ended up with James Nicholson, the deputy chairman and international head of the jewelry, silver and watches department at Dreweatts.

“Everything is 1970s and early 1980s apart from the watch, which is the only old piece, it dates from about 1920,” said Mr. Nicholson, who described the timepiece as typical of early wristwatches made for women.

“It’s just really very nice quality, very, very well made,” he said, adding that the sapphires and diamonds around the bezel “give it a little, you know, give it a lift to make it something quite, make it something more extraordinary than just a normal wristwatch of that period.”