PHOTO: Brett Blundy was ranked Australia’s 44th richest person in the 2017 Financial Review Rich List 200 with a fortune of $1.39 billion. Photo: Louise Kennerley.

It’s quite the upgrade. The mystery buyers of the most expensive house sold in Sydney this year are revealed as a low-profile Dover Heights couple who swapped their $7.8 million home for the Rose Bay trophy home of billionaire Brett Blundy, which had been on the market for about $45 million.

Of all the corporate heavyweights who take an interest in Sydney’s best real estate, Sylvia and Lawrence Myers have been remarkably inconspicuous house hunters.