good evening Geoff,
I am fully in line with the above answers:
the D520 were mainly used for school training and not against the allied forces.
Most D520 crashes in the South or South West of France are consecutive to student mistakes or mechanical failures.
May I suggest you have a look at Thomas Genth site, well structured, with plenty of beautiful D520 pictures with German markings, Thomas is telling the story of his father: quite fascinating.
http://www.thomasgenth.de/html/jg_101_pau.html
best regards;
GC