Hi, Having assembled R2 and switched on... no response (at all).

I had a look through the issues on here, and saw the comments re checking the battery volts, so removed the battery box to check all was well.

1) Batteries all show 4.11 volt individually when removed from box.
2) Initially, no volts on battery terminals in box (so testing across the silver metal pieces at ends of each battery space) - my battery positive 'buttons' not big enough, so added 4mm washers between button and box connection. Now I get 12.35v at diagonally opposite terminals in battery compartment (and 4.11/8.22 at intermediaries).
3) No volts at black connector at end of battery cable (the thickest cables), black cable is connected back to box (0 ohm on test back to battery compartment) but red seemingly not (it appears to be solidly connected both ends).

So, time for a new battery box or should I check anything else first?

Thanks