This car was built by John Jennison in Salisbury (A Northern suburb of Adelaide), in the late 20's. It's not clear when the photo was taken, from what I can figure out, after 1925.
Regarding what the car was based on, I think the answer that is required is Chevrolet. But, looking at the front on view of the car, that front axle and steering wheel are definitely from a Model T Ford, and by the look of it, the front cross member of the chassis as well; the car could have been made out of some Chev parts. That sump also looks T model, to me.