Many thanks to John for providing the attached pics..

John also provided the following info. :- “The original owner got it from Charlie several years ago and can’t remember much about it. He has given it to a fellow accordion player, sadly the AC power adaptor is missing so the new owner has passed it onto me to see if I can get it working. The finish leaves a bit to be desired and the PCB component layout around
the power input socket has been heavily modified, possibly a prototype !! Having examined the pcb I’ve noticed a copyright date of 1987″

The control layout is almost identical to the Digital Copicat in the Soundbuilder range so it is probably a prototype of that unit.