It would be my second robot, I also have a thwack bot made from steel box section.

I was unsure if the bulkheads would be strong enough, not worked with hdpe before, I could double the thickness around the anchor points or strengthen it with steel. I was also concerned if the 10mm thick steel would be thick enough for the claw.

How does your bot self right? I was thinking of roll bars to passively self right it, they would also protect the actuator from attack as well.