The first machine would have had a 14" inch cutting width and was, I argue, a smaller version of the UK's Hayter walk-behind commercial rotary slashers introduced in the mid-1940s. This was not a direct drive domestic lawnmower, but a small belt drive machine.
At this point I would like to make a research observation: some vintage NZ rotaries followed a different design path to some AUS vintage rotaries. Blades on AUS machines were directly coupled to their engines; many domestic NZ machines had a belt drive between engine and blade shaft (in the Hayter fashion). [NOTE: I mean only the earliest NZ rotaries. Later domestic machines clearly followed conventional direct drive designs]
The only AUS machine of similar design logic was the Grasshopper, first introduced here in 1951 in an electric variant. The later, petrol motor, was contemporaneous to Victa's 1952 start date and, arguably, may predate it. Amazing!
The machine (below) is a superbly restored Speediescythe owned by collector Greg S. It is fitted with a 34cc J.A.P. engine. Note the wooden front wheels, large rear wheels and skirted, pressed-steel chassis and tubular handles. No 'toe-cutters' in NZ!
Best guess is that this is a 1950's machine and I include a 1956 newspaper advertisement of its type.
A Special thanks to Greg S for bringing this important machine to my attention.