I wonder if there is a log of activity and faults maintained that Stannah could read from the PCB. Probably not as there doesn't appear to be any socket that could be used for testing / reading the chip ( one assumes it is a processor of some sort and not jsut a logica array ).
I am told that Stannah still produce stair lifts with cable to the chair. If that is the case then one wonders why this un-reliable battery in chair system is ever installed.