Gav, I'm very supportive of geothermal, and I'm also keen to learn more about it, but I think that little dot marked "Sydney Basin" on the map above is indeed the Hunter Valley "anomaly" near Muswellbrook that is controlled by Geodynamics.
(See small pdf = http://www.environment.gov.au/settlements/renewable/recp/hotdryrock/pubs...)

It doesn't sound to me like the whole Hunter Valley is underlain by this resource, just a 20km blob of granite about 5km underground in the Upper Hunter. (And it may need fracturing (http://www.abc.net.au/rn/science/earth/stories/s18546.htm) whereas the Cooper Basin already has good natural fractures and they have already got steam pressure between their wells.

Nonetheless, what a lucky stroke that these Hunter hot rocks are right under our existing NSW power generation and transmission infrastructure! I hope that Geodynamics make a go of it.

Thirra - the other point which Geodymnamics seem to emphasise in their latest quarterly report...
(http://www.geodynamics.com.au/IRM/content/shareholder_mediaroom.html)
... is that the hot rocks need an "insulating blanket" of about 3km of sedimentary rock on top to trap the heat. So presumably those New England granites sticking out into the rain, wind and snow are a bit of a lost cause.
;-)