Thanks for the review David, sounds like an interesting read.
There never did seem to be many photos of the Whirlwind, compared to other types, and it may be that it was regarded as 'secret' at the time, even when operational. Photography in general, other than 'official' photos, was banned on military establishments - even though 'private' snaps were taken - so if the 'Whirlwind' was given a higher security rating, then I'd guess the rules were enforced more than usual?