Hi Max
Many thanks for the insights.

Yep, totally agree about the louvred catcher design.

It is my belief that both Turner and Scott Bonnar (later) took
design cues from the great NZ company Morrison.

Rover, also, would use these louvres on their steel side-catchers.
Another approach was the use of round or square hole steel mesh.

I don't think too many of those Turner Morrison rotaries survive.
https://www.outdoorking-forum.com.au/forum/u.../turner-morrison-rear-catcher-mower.html

Cheers
-------------------------
Jack