Managed to make the prototype pcbs during the week but didn’t get to build the hardware until Friday after work.
Pleased to say that it works (after an hour or so tweaking the code and adding stuff I’d not thought about) although the pcb will need modifications to make it pupil proof. Bigger pads for soldering to mostly plus move the pot 1/10″ out. Since I’m using the A/D input as an output later in the programme I’ll need to add a couple of padder resistors as at each end of the travel it cuts the volume (as I thought it might). Added bonus from this is that on minimum the lowest bit lights, so that will save doing it in software.