Great work there, mate. I've got a few ideas like adding M8 and M3 nut traps to save on washers and possibly combining the Y bar clamps in some cunning way to eliminate even more M8 nuts.

I fancy doing a bunch of dayglo orange, but I'll have to get 30kg made up. Anyone want to split?

Thank you! I was wrestling with Blender to remove the three holes in the middle (to reduce print time on my uber-slow McWire), and after over a dozen unsuccessful attempts with its awful UI, I found this. It took me less than 5 minutes to do what I wanted to do in OpenSCAD.