I wonder if you could clarify if the P8 compass as pictured was used in the Spitfire? I originally bought a P10 advertised as for a Spitfire and didn't do my due diligence and it's larger for a Lancaster - still a beautiful thing!
The Type P8 Navigational Compass, Ref 6A/0726, was used with many aircraft of the British Royal Air Force during WWII, including Spitfire, Hurricane, Mosquito, and Beaufighter. The P8 was also used in British tanks up to about late 1943.