FWIW I did manage to demold the other footpad without destroying the mold, not that I’ll even use it again.
Speaking of footpads, finally got around to wiring up the sensors. Four FSRs wired into two parallel groups. I’ve not heard great things about this solution, but I guess I’ll find out. Must have done something to one of them the first time around as I found one of the parallel groups to be always closed 
I think everyone knows carbon fiber is conductive. I was curious though so stuck a multimeter to each end of my footpad, and sure enough, it really was quite conductive. Not a big deal, just means most surfaces the battery will come in contact with are conductive, it’s enough to cause a little concern.
Lined the aluminium and carbon surfaces with Tesa tape, and then another layer of 3mm thick neoprene.
Then the battery was stuck down to the polycarbonate base with double sided tape.
And then the enclosure gets sealed up for hopefully the last time.
Battery still charges, footpad sensors still work, and nothing rattles/moves 