I had a little talk to the guy diligently selling "Vietnam" badges. Or, rather, I lent him my ear for a couple of minutes. He was quite happy to tell his stories, but he wasn't much of a listener! Just for the record, he was an infantryman in 1 RAR.
And I'm not sure that I like the design of the badge (but I didn't tell him that), although I assume that it represents the Long Tan cross.