Just had a look at Dakin. Interesting bloke. Absolutely no military experience or qualifications on the requirements of battlefield camouflage but knew a lot about fish.
In the end, a camouflage system can only be judged subjectively by human observation and probably anyone with a bit of common sense could have come up with equally efficient, or inefficient, schemes given the facilities and trials he had access to.
Still, nobody in Australia was an expert in 1940, so they must have figured a bloke who knew how fish avoided being eaten must be just the shot for hiding tanks on a battlefield.
Lang
http://adb.anu.edu.au/biography/dakin-william-john-5863