@plebster as I understand it, the handle shape is the main difference: straight or kinked. The blade has to be presented flat to the ground at all parts of the swing, and the curve collects the cut grass and pushes it into the "windrow" ie line of mown grass left behind as the mower moves up the field.
@narayani there's plenty of other stuff for the bees at the moment - they cut it at the right time for the seeds to fall out of the flowers and set the meadow for next year
Did they explain why the difference in the blade shapes? Is it just operator-preference, or do they each have advantages and disadvantages, I wonder.
Ah, that's interesting, I hadn't even considered the handle. Thanks for the reply!