Brian Barker OBE (1979) The Symbols of Sovereignty. Wellington: Reed

I will refer to this second book from Brian Barker as 'Barker 2'.
In the Foreword, JP Brook-Little, Richmond Herald of Arms, says -
"The author, appreciating that until 1707 there were two kingdoms in this island, each with its own traditions,
ceremonies, symbols and regalia, has treated of both England and Scotland with equal diligence."

This second book from Barker throws a wider beam on the regalia and goes back before the 1953 coronation of course.