Hi chris,
I'm pretty sure this bike is an early 20's Ok Junior fitted with a Union two-stroke.
Humphrey & Dawes made these before they split up, each to go their own way. Ernie Humphries went on to form OK-Supreme.
I'd also swear the photo is Australian and was taken in a typical Australian backyard of the time. It looks just like my nanna's did when I was an exceedingly small boy. She was pretty old by then and I don't think anything in the house and backyard had changed since she'd moved in.
Cheers, Bob
