Hi Lu & others,
I have now been told that the photo was in a collection, found after someone passed away. But not named. It now seems likely then that perhaps one of my grandfather's siblings might have been the owner. There's William Charles Hart (b 1877 Christchurch) - not much known about him, and Clement Douglas Hart (1886-1953). Clem Hart later lived on the West Coast, after the First World War, along with his wife Mabel (1892-1957) and their daughter Mary Hart. Clem Hart died in Greymouth.
Could this be the missing link I wonder?
Printer