I've recently begun listening to this on audible and can't recommend it enough if you're interested in the royal family, the coronation and lives of the upper class in the 20th century in general. She has a wonderful cut-glass accent and narrates it herself wonderfully.
She was a maid of honour at the queen's coronation and she also describes George VI's lying in state at Westminster Hall so it is incredibly relevant and fascinating at the moment. It's called 'Lady in Waiting'.