This one was never solved conclusively on the yahoo group TramsDownUnder. I suspect just a few minutes, and top of head, for people here (so no prize, fizzy or otherwise).

Roderick B Smith
Rail News Victoria Editor

Photos:
7b _542 & _ Scammel R Youl (Red.).jpeg
tdu.to/34154.att
[seems to be the Blitz welding truck]

6507Me.25.12.jpg
tdu.to/34204.att
[seems to be the Scammell rescue truck]

7b?542 and? Scammell, Apr.66 (or maybe 1968)
...the truck beside is possible one of the work vans it definitely is not the Scammell.
...looks very much like an old ex army Ford or Chevy Blitz truck from the WW 2 era they were fairly common 1960s.
...Appears to have been remotored, - different radiator. Getting a lot less common towards the end of the 60s.
...Would this be the vehicle to which you refer? This one was a Scammell and was used by BCC to tow diesel/trolley buses when they broke down, as in this case in July 65.
...The breakdown wagon looks like a Blitz to me.
...No, I think it is the Scammell which is preserved at Ferny Grove, operating I believe.
...It isn't the Scammell but most likely the Ford Blitz welding truck; both vehicles now owned by Brisbane Tramway Museum.
There is a good photo of it in Last decade on p42 at New Farm Jn.

First one looks like a WW2 Chev or Ford Blitz and the second one is also of WW2 vintage and is a Scammell Pioneer .... used as a tank transporter mainly for the British......

Geez Roddy that took as long for me as it did to open the files ;D ;D ;D :

First one is a CMP (Canadian Military Pattern) Ford or Chev-Blitz as the Aussies call them. The second one is a Scammell Pioneer-would have a 102 h.p. Gardner 6LW diesel.

They had several Blitzes in BCC Department of Transport will look up the records and find this one. The Scammell is in the livery of the way it was introduced before everything was painted yellow and yes it has the Gardner as this was also fitted to the Daimler buses and I still remember a spare engine for it sitting outside the pump room at Toowong.

In the end (1980) the Scammell was put off the road for a worn king pin and inefficient handbrake. There was a lot of interest from Military and Qld museums around the country wanting to give "Scamp" a home, after stories about it in the Post and Courier Mail, but Council decided to keep it in Brisbane.
She was purchased direct from the Army back in 1944 at Mt Gravatt military park for around 1200lb according to the despatch docket and Stores Board documents. It saw service in the Middle East.