WWII Clandestine Photo Reconnaissance

Yes I read your reply. I'll try to find that old Icare issue but, as I said, there are no details, only that a severely guarded recce-Spit was in a hangar on some French airfield. The only detail I could find is the name of this airfield. Stand by, be patient.
As for SHAA, now unified military archive (I have forgotten the new name), I am surprised by their behaviour. Try to ask them again but IN FRENCH, it could work. As a last resort you could announce your visit there, at least one month before (preferably 3 months before, repeating the announcement 1 month before) - except if you write or phone them and they tell you it's all right - and go there. After all it's virtually Paris, not so far away.