For the electrical and shore power adaptation, I am trying using a Step Up transformer. at least as a first step.
It was easy.
and inexpensive (about 40euros - versus about.... 1000euros to buy and ship a new 115v 12v charger and replace the wiring to the AC outlets)
the 2000W transformer is quite light and small
i've placed it in the rear storage area and modified the exterior socket to take 115V to the transformer and then the wiring that was connected to the Commando socket runs 230V from the transformer back to the original 12v battery charger
Nothing blew up or melted or started smoking.

(I will tape up those connections today and tuck them safely away)
With all that in place there is 230V power at the 3 AC outlets inside when on Shore Power.
But I remain a bit confused.
I think the 12V charger "should" maintain the charge on the Starter battery (from the two prong connector)
but having left the system running overnight the Starter battery only shows 12.06V - which I think is a bit low (isn't it?)
Looking at the 12V battery charger again, I don't get any reading with my multimeter across the two slots of that Start Battery connector. 0.00
and is it normal that there is only one wire on that connector? (see attached photo)
the wiring diagram seems to show a + and a - for the Starter Battery.
and I am getting no reading (0.00) at the ports that should be feeding the 12V Versorgung batteries
Blown Fuse (in the 12V battery charger box)?
I'll check that next.