Hi Dince
As the Forum Historian I am interested in these odd machines.
They also represent a 'crossover'; between agriculture and horticulture.

I am convinced that the design originated in the agricultural sphere,
rather than the horticultural. A single wheel could follow furrows on farm land.

The sickle-bar mower was invented for agricultural use, but cutting grasses for hay
is not so different to cutting horticultural grasses. This is what transpired.

Enter the Allen Scythe, The Mountfield, the Gravely, the Atco ... and etc.
I think Ransomes, Gravely and Atco made single wheel designs.
But two-wheel tractors prevailed.

Early post-WWII there was an explosion in the use of sickle-bar mowers,
probably brought about by urban expansion. But this would be short-lived,
when another explosion occurred - the rotary revolution killed the sickle mower.

I suspect that is one reason why these machines are misunderstood, and
few survive.

-----------------------------
Jack

p.s. for the record, we would love to see some images of your Atcos.