What a productive evening! I received a big bag of M6-2 clinch nuts in the post today and I decided to install them! Clinch nuts are a special type of nut that you press fit into a hole (8.75mm for M6) and the metal cold forms to lock the clinch nut in place so it doesn't drop out or rotate. It's ideal for putting threaded holes in sheet metal or in my case regularly used threaded holes in 0.125" aluminium channel.

Last night I used a CNC Router to cut out the bottom sheet of polycarbonate to ensure all the holes were in the correct spots. I also attempted to cut out the top sheet of polycarbonate but I made a mistake and while all the inner holes and cut outs came out correctly unfortunately the perimeter was not cut correctly. I've also fixed this tonight.

Put both completed tasks together and I have top and bottom armour that I can mount to the inner chassis pieces:


I cannot attach the front/side armour plates in that picture because I still have some work to do with the front wheels but soon that will be sorted.

My next tasks are to strip the outer chassis pieces, the wheel pods and add clinch nuts to them so I can fully bolt the polycarbonate down. I also need to finish mounting the battery and electronics.