"They thought we were brave to take it on," adds Alison. She recalls Peter telling her he thought it would take six months to get the house back to one dwelling but, it was actually five years before all evidence that it had been divided was gone, and the restoration continued for many more years after that.
Peter is a lawyer but also a skilled woodworker and furniture maker and did most of the work himself, toiling at weekends. Over the years he has spent many, many hours in the enormous basement workshop that occupies the width of the house, meticulously working on enhancing his home's beautiful period features.
For example, although the striking wood panelling in the entrance, lounge and dining room is original, some of it needed to be restored after being hidden behind gib board. Peter took enormous care to make sure new items - such as battens on the panelling and also the doors and windows - were made to match the rest of the house.
Today, the house is a tribute to the skill of great craftsmen - not just Peter, but also to the workmen who built it back in the 1920s. It has been updated for the 21st century without losing any of its character and style and, while it is an undeniably grand house, it is also a comfortable and welcoming home that is ideal for a family.
One of the things Alison particularly loves is the semi-circular drive in front of the house, which sweeps under the portico. There's a big front porch which opens into the impressive mahogany-panelled entrance hall, complete with an inglenook with a built-in seat.
To the left is the spacious formal lounge, which opens into the dining room. These are also panelled, this time in rimu, and the dining room has an original fireplace still in working order.
At the rear of this level is the family room, dining area and the stylish contemporary kitchen which has a central island with a limestone benchtop. Off the kitchen is a large cupboard, powder room and the laundry.
The dining area has several sets of French doors opening out to the partially covered veranda, which looks out over the northwest-facing garden. The expansive lawn provided the perfect spot for the wedding of the Fergusons' daughter.
Upstairs are the family bathroom with separate toilet and five big bedrooms, including one currently used as an office. The master bedroom has an en suite and wonderful views of the Waitakere Ranges. There's more evidence on this level of the carefully preserved period features such as the tongue-and-groove ceilings.
There's also a third level downstairs, reached via a second staircase off the ground floor hall. This accommodates the workshop - which would also make a good wine cellar - and a large rumpus room with doors out to the garden. A bathroom is also on this level.
The Fergusons say the house was a wonderful place to raise their three children but, now Peter's about to retire, the couple are keen to divide their time between two other properties they own, which will become "projects".
"There is more I'd like to do to this house but you can't go on forever," says Peter.
