They're Going Backwards!
The '64 ad looks like a C-4, with front skids instead of casters. The C-5 in the first post with the single front caster is a rare model made for about three years in the early '60s to replace the C-4, by '64 the C-5 had been replaced by the C-6 with the double front casters that remained for the rest of the life of the original design through the TriStar years. I'd love to see the bottom of that C-5, was it made in Anaheim, California or Australia? Maybe they imported the C-5 for a few years and then sent the old C-4 molds over and made that in Australia.
Thanks for posting, this is an interesting offshoot of the Compact/TriStar story. TriStar itself seems to have little interest or knowledge of their history so it's nice to fill in some gaps. Was the Pinnock sold exclusively through stores or also by door to door salesmen like Compact? How long were they sold or made in Australia?