Daryl, you are correct, it's a real pet hate of mine, I think many Australians are too dumb to know the difference between a hexagon and an octagon, sadly...
I was only speaking to a mate of mine about this very rifle yesterday, he thinks it's because they are too lazy to say "octagonal" and "hex" is easier and faster. Happens here all the time with Winchester lever action rifles, "it's got a hex barrel".

Whilst the 600 is a very nice looking rifle, and the guy that built it is entitled to have it made however he wants, it's his money, but an American style barrel an an English action just doesn't do it for me.