Things have progressed since my posting that notice. I have recently published a family history with two chapters on the Davy family. The book is called "From Brecon to Broken Hill; the History of a Wilkins Family" and a copy is held at Wellington, Auckland, Christchurch and New Plymouth libraries.
If you can have a look there hopefully it will answer some of your queries. Did you know, for example, one of the Davy family (Ned) was in the first NZ rugby side (1884, before they became known as the All Blacks)?