EWinstanley on Family Tree Circles

I am looking for ancestors for my grandfather, John James Winstanley. I am unsure of his birthday but he was born in New Zealand, somewhere around 1914. He married Sophia Millistone (it's spelt Millerstone in NZ electoral rolls)MacDonald around 1940. They had the following children;

Donald William 1941 - Living
John Arthur
Sanchia Margaret
James ?

I've not had any luck finding ancestors for my grandfather. I've looked on Ancestry.com records and scoured through NZ newspapers to no avail.

I'm not sure if it helps, but Sophia's parents were James MacDonald 1878 and Caroline Creed 1883.

I hope someone out there has some information