Wensleydale - In 30 years of dealing I had about two examples of these badges pass through my hands. Saw a full set at a collectors fair at least ten years back with an eye-watering three-figure price-tag. Good luck to the Waddington Heritage Centre!
Incidentally Whopity, the officer about whom I made some less than complimentary remarks was not the Gp Capt King you refer to - never ran across him. My man had better remain anonymous!