Post-war austerity possibly dictated that the original, single level, two-bedroom home had mainly modest bedrooms and living spaces apart from two grand front rooms facing Mountain Rd.
The Cotters commissioned architect Terence Hitchcock to design an extension that would respect Massey's original design, integrate its best features and retain the trees.
Hitchcock, who had worked on some of Massey's other homes, added a second storey to accommodate three new bedrooms and an open-plan office off the upstairs landing that is separated from the master bedroom and en suite by a sliding door.
The original south-facing kitchen was moved to the north side to adjoin a light-filled family room, dining room and elevated patio that all look out over the garden. This level also includes a large formal living room next to a spacious library.
Large panelled windows in these rooms and throughout the house have peaceful views out through the trees to the established, well-landscaped garden of low maintenance plants - clivias, rhododendrons and ferns.
All the rooms are well proportioned and feel like discreet spaces, while connecting effortlessly with each other.
"One of the things we have loved about living here is that everyone feels as though they have their own space. Even though it's a relatively large house, it feels friendly and has a great human scale," says Monica.
The Cotters' quality renovation included putting solid hardwood parquet floors in the kitchen, dining room, family room and foyer. "We've sanded them back and repolished them every five years and they look brand new."
Apart from adding a large window to the fourth, south-facing bedroom on the ground floor, the Cotters have made no structural changes to Hitchcock's original redesign, which has stood the test of time. Cosmetic changes have included recarpeting and repainting, plus meticulously maintaining the house and garden.
As well as the original single garage, the house's bottom level has a large storeroom and workshop that opens to the garden.
With both of their adult children living overseas, Chris and Monica spend more time travelling and no longer need such a large house.
"It has been a privilege to live here. We've felt as though we have been custodians of the property and its trees."