It has been lent to me by a gent whose father worked for GMH in Adelaide for 25+ years and finished in a reasonably responsible position in engineering. I think he retired in the mid 70's as he was sold his company HQ Holden on retirement.
I will take a picture of the cover next week (it is back at work now) and post it up. It just has a large 25 on the front cover. There are lots of production shots of the models from 1948 to 1973, including engines (and V8 development). It has very little technical information, just overviews and I saw the photo of the SS as one of real interest.