This plain bearing .29 cuin. RRV glow-plug motor was acquired by Australian resident Goran Milosavljevic at the 2019 Oily Hand meeting in Cowra, Australia. The engine is very well made, with good fits throughout. Note the circular head fins, reminiscent of the early post-WW2 Cannon engines from America. 

The engine is assumed to be of Australian origin, although this is not certain. Looking at it, I'm fairly certain that it's a home-made effort by some very capable maker, but I could be wrong. Goran has checked with other Australian model engine aficionados, who have been unable to identify it. Can any reader help??