These was a guy by the name of Stew from your neck of the woods who made some really nice axle nut covers. I bought a set just before he shut down his website. His site resided at
http://www.srschrome.com/index.htm but is no longer around. I provided this information because I suspect if a guy was to hunt him down, he would still have a set or two of those beautiful spiked axle covers kicking around.
That's all I got. It's a long shot but google the heck out of Stew and his Triumph accessories from your land Down Under and ya never know... you just might end up getting what you're looking from your own back yard. Good luck, my friend!!
