Because any rendering of a specific crown can have so many variations, I present two Royal Air Force versions on the one British Crown:
https://airlineartifacts.files.wordpres ... erware.jpg
I suspect the decorations on yours are not all for "pearls", but rather jewels. Maybe just a hunch but archaic lion supporting shield coupled with script "g" just seems to scream "George". Of course that does not mean people from MI-(select a number) will be at your door inviting you to a "light tea" at Scotland Yard on your way to the Tower of London ....yet.