I have been following this discussion with some interest and I also feel
that the recording is unlikely to be genuine. Not only is the lack of
noise a problem; I also have some difficulty in believing that the disc
cutting machinery at that time was capable of being sufficiently
isolated from the considerable vibration and G-forces due to combat
Doctored, or even completely phony information for propaganda purposes
(and let's face it this was pure propaganda) were, and still are,
common. I used to have a recording of famous wartime speeches by
Churchill and other WWII leaders and on the notes was the comment that
some of the cuts were re-recordings due to the poor quality, or total
lack, of original recordings. Unfortunately I transferred this to tape
many years ago and no longer have the liner notes with the details, but
I am quite certain that at least one of them was a well known speech by
Churchill which was re-recorded in a BBC studio.
I'm tempted to consign this to the collection of "official" items
containing such things as "Cats Eyes Cunningham" and his carrots, which
was widely believed at the time; and probably still is by some.
It would seem likely that at least one person involved in this recording
is still alive and could provide the truth - unless it is covered by the
Official Secrets Act, as much WWII detail apparently still is.