Sydney's best trophy homes that nobody knows about

For the uninitiated, Elaine is the most expensive home ever sold in Australia, having set the bar at $71 million earlier this year when the Point Piper estate was bought by billionaire techie Scott Farquhar and his investment banker wife Kim Jackson.

It topped the $70 million high of 2015 set when casino mogul James Packer and his former wife Erica sold their Vaucluse trophy home, La Mer, beating the previous $52 million paid in 2013 for the Point Piper waterfront mansion Altona.

But these are not the only homes that could fetch these prices. Australian John Symond was offered more than $100 million for his Point Piper mansion when it was recently on the market, although he opted to keep his palatial Sydney bolthole.

Then there's the Bellevue Hill estate Rona and the Elizabeth Bay waterfront trophy Boomerang, both being shopped around to high net worth buyers.

Less known are the secret estates and mansions long held in the one family, privately set behind high garden walls and of a size best appreciated from a Google Earth vantage point. They remain the best option of ever setting a national price record, if only they were up for sale.

Uig Lodge, Wentworth Place, Point Piper

Uig Lodge at Point Piper was passed in at its 1996 auction at $10.13 million.

Set at the top of Point Piper on a 3300 square metre double block is the grand Scottish baronial mansion built by inaugural commissioner on the Sydney Harbour Trust and founding member of the Royal Sydney Golf Club, Lachlan Beaton, after he bought the site for ??3925 in 1901.

Previously owned by publisher Ezra Norton and politician George Frederick Earp, CBE, it last made headlines in 1996 when it went to auction on behalf of the late white and electrical goods businessman Aldur Kaljo. ???It was passed in for $10.13 million but later sold to rag traders Stephen and Carol Moss.

An extensive renovation has made it one of the most sought-after non-waterfront trophy homes in Sydney. Buyers have approached the Moss family over the years with no luck.

Mr Kaljo had bought it for $500,000 in 1976 from Mr Norton.

Fairwater, New South Head Road, Point Piper

Fairwater is the Fairfax family's larger estate, next door to the family's recently sold property Elaine. Photo: Ben Rushton

The Hermitage at Vaucluse is owned by bar baron Justin Hemmes. Photo: Dallas Kilponen

There is no secret about the owner of The Hermitage, thanks to the high-profile lifestyle of pub baron Justin Hemmes, but less known is his home's status as one of the finest on Sydney Harbour.

The heritage-listed Gothic residence dates back to 1840 when silversmith Alexander Dick built a cottage that was extended in the 1870s by Edward Mason Hunt.

When the late hospitality legend John Hemmes bought it in 1975 it became the first home in Sydney to break the $1 million barrier.

Justin moved in to the 4978 sq m waterfront estate in 2011 and architect Brian Hess of Hess Hoen has overseen a renovation of it in recent years.

Carthona, Carthona Avenue, Darling Point

Carthona at Darling Point has been held by the Oxley family for three generations since 1940. Photo: Nick Moir

The Gothic Revival residence set on the promontory of Darling Point was built in 1841 by the fourth Surveyor-General Sir Thomas Mitchell. The heritage-listed residence had a stint as a girls' boarding school from the 1850s and last traded in 1940 when bought by Philip Bushel, of the Bushell's Tea family.

Three generations later it remains in the family, having been passed on from Bushell's Tea heiress Amber Oxley to her son Tony Oxley and his wife, art dealer Roslyn Oxley.

Its financial worth has not been tested in almost 80 years.

Milthorpe, Crescent Street, Hunters Hill

Lang Walker's Milthorpe estate is one of the best properties in Hunters Hill. Photo: Quentin Jones

The historic Milthorpe estate in Hunters Hill is unlikely to beat the national house price record but at 7280 sq m it deserves mention as the largest privately-held property on the blue-chip peninsula.

Built in the 1870s it last traded in late 1986 when billionaire Lang Walker bought it pre-auction for $4.25 million and after a local battle to preserve the estate from subdivision.

The entry to Lang Walker's Milthorpe estate in Hunters Hill. Photo: Louise Kennerley

Set on 30 metres of Lane Cove River frontage the estate includes a sandy beach, tennis court, pool and a private jetty that is home to Walker's prized float Kokomo.

Its worth remains unknown, but would command top prices for the North Shore, easily topping the recent peninsula record of some $23 million set by the Federation waterfront property Vailele that sold earlier this year.

Hawthornden, Roslyndale Ave, Woollahra

House at 6-12 Roslyndale Street, Woollahra. Photo: Simon Alekna

The colonial Georgian residence of Transfield director and philanthropist Luca Belgiorno-Nettis and his wife Anita was set for demolition in 1995 when TV operator Sam Gazal planned to sell it to developers to make way for 11 dwellings over five storeys. Community outrage and heritage concerns won the day and it was instead preserved as one of Sydney's oldest 19th-century mansions.

It wasn't the first time it had been under threat of demolition. Gazal beat developers to buy it mortgagee in 1978 for $650,000, and promptly subdivided off the top block for $136,000 to the late Alan Bond, who then onsold it for the same amount.

The 1858-built residence now sits on 6521 sq m with a century-old garden set behind the original sandstone entry gates with a tennis court, pool and historic five-bedroom home that was extended in the 1920s by Hardy Wilson and again in the 1980s with a Douglas Gordon conservatory.

The Belgiorno-Nettis family bought it in 1999 for $7.7 million. Eighteen years later it has never been offered for sale.

Glanworth, Lindsay Avenue, Darling Point

Set at the northern most tip of Darling Point is a rare example of American antebellum-style of architecture known as Glanworth that was built in 1916 for an American from Buffalo, Peter Britz.

With views from three sides over Sydney Harbour and privately set behind tiered landscaped gardens, it has long been owned by notable art collectors in the century since, including its current owner, media tycoon Kerry Stokes who bought it in 1998 from Singapore businessman Ho Whye Chung for $9.5 million.

Ho only owned it for four years, having bought it for $8.5 million in 1994 from the late philanthropist and arts patron and collector James Fairfax, who had owned it since 1966. From the late 1920s it was owned by another art benefactor Samuel Henry Ervin, who died in 1977 and bequeathed his estate to the National Trust.

Glanworth's waterfront neighbour was sold by the late Sir William Tyree, OBE, in late 2013 for $32 million to retired investment banker and yachtie Matt Allen, who promptly undertook a DA-approved major renovation and extension.