The price represents a loss of more than 11 per cent for Albert Bertini, the flamboyant property developer who paid $22.5 million for the 1485-square-metre Hopetoun Avenue waterfront property four years ago.

Land and Property Authority records reveal the purchaser was Ros Oatley, who lives next door at Rivendell, a 2000-square-metre property with a mansion and tennis court that sold for $15.5 million in 2001. She is the daughter of Bob Oatley who sold his Rosemount wine business to Foster's for $1.4 billion in 2001.

The Bertini house, known as Kahala, sold on November 18 through Raine & Horne Mosman agent Brendan Warner, who refused to discuss details.

However, Mr Warner confirmed 12 parties had inspected the property since it hit the market in early October.

"Four people showed interest in buying the property during its expressions of interest marketing campaign leading up to the closing date on November 17,'' said Warner, who also handled the 2007 sale.

Hopetoun Avenue boasts a who's who of residents including artist Ken Done and liquidator Max Donnelly.

Since buying Kahala, Mr Bertini has secured development approval to rebuild the three-level house. The DA also applies to the construction of two pools, two garages, a separate staff building (with two apartments) and a $1 million tunnel with a James Bond-style subterranean lift to the boatshed.