Pontius Nav, I wonder if the civil servant that you refer to was a Mr Barley (Phil I think) working out of Farnborough, he of Barley Grey fame. a world class specialist on concealment tucked away in a tin shed. He was amazed that the paint finish on RAF aircraft was dictated by the requirements of the engineers rather than that of camouflage and was most insistant on things like the gloss content of the paint. An unsung hero in his way.