Today I stripped it right back.
I cut a 12mm strip off the front and sides leaving some pieces as a ledge for the HDPE armour.
Widened the wheel slots a bit,not much weight saved there.
Also drilled a heap of 10mm holes in the base and some 50mm holes in the HDPE sides and back.

I also cross drilled all the rubber of the wheels but to be honest I saved very littleweight. I think the weight is in the hub.
While I had the wheels out I checked the fitting and replaced those pesky nuts with locking nuts.
Refitting the wheels on the axles took about of work but I am happier in their location,and the clamps are tighter to stop movement when rotating

Swapped out the motor retaining nuts for locking nuts.
Tightened everything else up.

I should have shed perhaps 200g. Fingers crossed.

Refitting it all back together now. Fitted some of the pond filter foam around the electronics, and under the battery. Tidying up some of the cabling.

Tomorrow I want to refit the shell,and test everything still works.before bolting it all in place again. Then it's fitting on the front armour and building and fitting the ramp, including the self-righteous mechanism, and sides.

I could do with a day off work.