Can anyone identify where (or era) this spadegrip comes from based on the camera only button? I’ve yet to see a spitfire/supermarine grip with this feature. Thanks

definately late Spit……the finish is commensurate with a late covering fitted to the later super spits/seafires….griffon powered….see on my project:
http://www.airdefencecollection.co.uk/Spitfire.htm
and on my seafire cockpit too