For what it is worth, the excellent Spitfire production list at
http://www.airhistory.org.uk/spitfire/p036.html has Clarke lost in EN784, but lists it as "abandoned over the Channel", which doesn't match this photo. BL964 is reported on the same set of web pages as failed to return on 26 July 1942. Does anyone have the 412 Sdn ORB for this period, or any POW reports by Clarke?