williamwright wrote:

It is absolutely impossible to obtain maintenance instructions, circuit
diagrams, etc.


I found Acorn user/installer/schematic/training manuals, they seemed to
also apply to a Brooks model. Batteries were not that difficult to
replace, also managed to get a replacement PCB from eBay when it burned out

There are a very few freelance maintenance guys but even
they can't get any info.
Most models make it very difficult to replace the batteries.
(Incidentally most machines use two 12V lead acid batteries in series.
The skirting board mounted chargers are 33V 1A or 2A, and there is
charging regulation in the machine. I have been asked for £200 for one
of these chargers by a manufacturer's agent. A far better quality one
can be had from RS for about £40.