It's actually this one http://www.buchananmotorcompany.com/images/Buchanan%20Holden.jpg I believe it's the ex-Jim Wright car that raced at Bathurst in 1958 & 59 before being sold onto SA. http://www.buchananmotorcompany.com/images/buchanan%20tr2%20jim%20wright.jpgYou can tell by the white paint under the front lights and the the lack of cutaway on the front wheel arches. Only a small number were built without the cutaway, this being the first.
Just in case you couldn't view the 2 photos mentioned, I've reproduced them above. I'm still having trouble working out which one it is in the register section in the Buchanan Motor Company website that Roo organises.