Hi SpitVIII!
I've seen those photos too. Most notably Richards Evans holding a curved trailing edge version.
http://combatflyers.co.uk/planes-index.htm To fit into the Australian Vintage rules the plans have to have been published before 1971 (Inclusive?).
I'm building Richards Ironmonger for this years Australian Nationals, 3 off, but I would like to be building the Anduril.
Somebody at combatflyers.co.uk will know. If I get any further and get hold of other plans, I'll post details here.