Provenance:
Queen Elizabeth The Queen Mother (1900-2002); the notelet case gifted to her by her husband King George VI on the day and occasion of their Coronation in 1936.
Queen Elizabeth II, from 2002 on the death of her mother.
Norman St John-Stevas, The Lord St John of Fawsley (1929-2012)
British Conservative politician, author and barrister; gifted to him by Queen Elizabeth II…’The Queen Would Like You To Accept This, In Memory Of Queen Elizabeth The Queen Mother’ https://en.wikipedia.org/wiki/Norman_St_John-Stevas.
Thence by descent (and never previously on the market).