Don't know the answer to that one. But a couple of years ago I listened to a talk at the Melbourne (Australia) branch of the Aviation Historical Society, by Tony Gaze DFC & two Bars who flew Spitfires alongside Johnny Johnston and Douglas Bader.
In those days camera gun evidence was used to confirm the success or otherwise of attacks on the enemy. Later marks of Spitfire had the camera gun ports removed to make way for a fuel cooling matrix for the then new two stage supercharger.
Without camera evidence this made definate evidence of a "kill" difficult to attain. To ensure certain confirmation of a shoot down, some pilots followed the diving enemy aircraft for a lot longer than was prudent and several were shot down in the process.