Is anyone in this discussion referring to the
National Archives online catalogue? Obviously it doesn't offer certainty as to files' content (only visiting and doing the reading will really do that) but I'd have thought it would eliminate some of the conjecture in this thread.
As I said the AHB 6 microfilms I saw at the IWM contained material in German; the AIR20 files I mentioned are in a sequence entitled "GERMAN (OR ENEMY) AIR OFFENSIVE AGAINST GREAT BRITAIN (Code 45): Translations from Captured Enemy Documents."
I haven't noticed any duplication between the two but neither have I read everything in both sets of material, I was following up specific lines of enquiry. The IWM microfilms for example include the
KTB of Stab JG 77 which I spent a very long time translating into English, something I probably wouldn't have done if I'd found an English version first.
By the way, you'll find ADI(K) No. 351/1945 at Kew on AIR 40/2423.