Going to update this thread with what’s happened with the board and some pictures.
In March Nexusboards finished the battery build, and my friend successfully installed it, using velcro to secure it in place in the enclosure.
One tiny issue was that the ECS wasn’t responding to the Robogotchi or remote signals when turned on. Turns out this was the culprit:
Those are the e-stop pins on the stormcore!
Luckily thanks the Lee Wright’s stormcore disassembly video I got my friend to open the ESC up and snip those pins off the board. They had likely shorted somehow from the connector getting bent. With the pins snipped the ESC behaved like normal again 
Final enclosure layout was such:
We also noticed early signs that the battery build wasn’t up to the quality we had hoped for:
With that wire insulated and more foam added, it was time for the butyl tape to water-seal the board
After the threadlocker cured and the mini remote was recalibrated, my friend could finally enjoy the board he’d been waiting so long for 
Enclosure started picking up scratches due to the Brits not having invented curb ramps yet:
