[robcur]

Thanks Mike. That's the one. I believe that 4 Sqn were operating from Gilze Rijen in the Netherlands at the time, having just taken over the airfield from the Luftwaffe. I'll add your information to the facts I'm building up for his son and grandchildren.
I did find a site for Luftwaffe day fighter claims which had just two Spitfires claimed on that day. Both were by JG77 but apart from the names of the two pilots, there were no further details.