At the time of her death, were there any surviving witnesses to the coronation of Queen Elizabeth II?
(interested in actual witnesses, not TV/radio witness. Witnesses who witnessed with their own eyes!)
As first meantioned by @davidlol: His Majesty King Charles III, aged 4, was present at his mother's coronation.
Lady Anne Glenconner, who became 90 on the 16th of July 2022, was one of the maids of honour at the coronation of Elizabeth II in Westminster Abbey.
2022-10-11: BBC News - Coronation on 6 May  for King Charles and Camilla, Queen Consort
1953-06-02: Coronation of Elizabeth II
The then Prince Charles, at the age of four, was among the guests watching his mother's coronation.
2012-05-31: Prince Charles shares stories of his 'Mama' the Queen in BBC tribute | King Charles III | The Guardian
In it he recalls how, as a four-year-old, he watched his young mother practising with the heavy (2.2kg) St Edward's crown ahead of her coronation. "I remember my Mama coming, you know, up, when we were being bathed as children, wearing the crown. It was quite funny – practising," he says.
2020-10-22: My Life In Seven Charms with Lady Anne Glenconner on Apple Podcasts
Lady Anne Glenconner, who was Princess Margaret’s lady-in-waiting from 1971 until her death in 2002. She is the daughter of Thomas Coke, 5th Earl of Leicester and his wife Lady Elizabeth York.
Speaking on jeweller Annoushka Ducas’ podcast ‘My Life in Seven Charms’, Lady Anne told the tale of the young prince’s immediate fascination with his mother’s glimmering crown, which could so easily have resulted in it being smashed to smithereens.
Lady Anne also revealed that the Queen would wear the crown while she was writing letters, saying: "I think Prince Charles says he remembers going in and seeing her [wearing it]. And asked her why she's wearing it and she said she was practicing."
"I wouldn't dare touch it. No, no, completely sacred," Lady Anne said. "Prince Charles got his paws on it, however old he was, when we got back to Buckingham Palace.
"Because [the Queen] took it off, put it on a table, and Prince Charles made a beeline for it. And we thought he was going to drop it. We thought, 'Oh my goodness, that would be a bad omen'. But luckily, I think my mother, as a lady-in-waiting, seized it from him and took it away."