Good pics there, tubes.
Going by the very distinctive cutter depth adjuster mechanism, I'll call this one as an 'Ings' Engineering' machine, made in WA. The maker was still in business, last time I looked.

This past thread has pics of a few Ings' edger variants, tho' none are quite an exact match for yours. https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=54475

Cheers,
Gadge

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