My grand-father, David Norman Hainsworth was born in Leeds in Yorkshire in 1905 and moved to Australia with his family. He married Dorothy Pritchard and they had 6 children, my mother was the youngest. After serving in the Royal Australian Navy, he joined the Australian Army when World War II broke out. He fought in the Pacific where he was wounded and after his return to Australia he had to have his leg amputated. He died in July 1969, 3 months before I was born. But my mother can tell you more about him.
I'm not sure if this is the same David Norman Hainsworth you are referring to. But if you think it might be the same man, you are welcome to contact me.