"I remember thinking we need one about New Zealand."
But raising a family and working proved busy and the research Diane had been doing to start her novel was put on the back burner.
"Even though it's fiction, if you're talking history you've got to have your facts right so I would go to the library while my husband was studying to research.
"I started making a lot of background notes, but it really wasn't the best time to start writing a book."
Teaching, hosting exchange students, working at the Christchurch Information Centre and running a bed and breakfast has kept her busy along with family life and moving cities a number of times.
However, despite the big writing break, multiple careers, and trauma after losing their house in the Christchurch earthquakes, the synopsis for the book remained the same.
"The details have developed over the years, but I always had the 100 years in mind and that the great-grandchildren would climb the tree at the end."
The book is based around a symbolic acorn planted upon Joseph Hamilton's arrival in New Zealand in 1868.
It follows the family through adventures in New Zealand and across the world to 1968, when the great-grandsons of Joseph Hamilton climb their great-grandpa's mighty oak tree.
Giving up golf last year, largely due to arthritis, was one of the catalysts for Diane to get the book finished.
With her golfing friends asking her what she would now do with her spare time, Diane said, "I'll finish the book I have mouldering away in the cupboard there".
Not sensing a lot of belief from her friends, Diane knew now was the time to work on it.
So she set aside time twice a week where she would head down to Paraparaumu Library and write for a few hours.
"It would just pour out of me, I would look up at the time and hours would have passed.
"It's a huge relief having finished it now.
"The family are also very thrilled."
Diane's cousin would ask how the book was coming along every time she saw her over the years and it was always a bit of a mumbled, vague response.
"It's a great sense of satisfaction to have completed it.
"I know in the 45 years between start and finish there has been a lot of ground covered in the New Zealand historical fiction genre.
"But I stuck to my guns and have finished it, for the grandchildren as much as anything."
With a lot of research to get the facts right, the historical fiction novel covers both world wars along with a great amount of family drama.
Great-Grandpa's Tree is available for purchase from Diane, email her at dmross45@gmail.com or call her on 021 029 16098.
