A google search shows West Island as part the Cocos (Keeling) Islands,there was an air strip there during WW2,I suppose they had spare time and kept active with motor cycle sprints.
I believe that’s a mega, and the fuel tank must be underneath him , AV gas was pretty good stuff back then , bigger carb and lots of other stuff that Ian and others could tell about , very cool
email (option): warbikes@gee male dit cum , you need to think about the address