I've been wondering this too- and have tried to find out when the Gay St Property was sold.
According to Perth Now/ Sunday Times, the subsequent owner subdivided it;
"Their former home in Gay Street, Huntingdale was subdivided by a subsequent owner with a new home built on one part of the block"
[FONT=Merriweather Sans, Helvetica, Open Sans, Arial, sans-serif] And, looking at Google Earth/LandGate, the property at 144 Gay Street has been there since the 80s, which would make sense as that was where he grew up? 142 Gay Street, or the property on that part of land was only built in 2010. (I'm assuming this is the subdivided part).
If I have this wrong, or if any one can clarify that would be awesome[/FONT]