'Mercman from oz' let me know (many thanks) and confirmed that it's a 1934 Ford rear body to chassis mount...then a while later I was also able to get in touch with the owner of the part.
It apparently was removed (in the 1970's) from the remains of an Australian bodied 1934 Ford Sedan
that had been dumped at a rubbish tip.
I'm missing this part...and will be purchasing it for our project.