I think I've found one, this instrument is in both the Spitfire and the Hurricane:
In the center of the Turn and Slip face it should say 'AM' below the crown, not 'AN'. 'AM' stands for 'Air Ministry' and this type of marking is found on everything from aircraft instruments to flying gloves, there were different styles but usually appeared in the form of 'A <crown> M'
Here it is on the placard from a late war radio management box:
