Thank you for helping out.
I am located in Denmark (bought the boat 2 weeks ago in France and sailed her back here).
Olivier did the survey, and he confirmed the 24V alternator was charging at that time (a week before I took over the yacht).
He did not mention the alternator being non-original, and that the red lamp was out of order.
I hope it is the original alternator, and that it is isolated as required, to prevent galvanic corrosion!!!
Maybe I could ask for a picture of your installation, if you are near the boat, and possibly the full part code of the alternator on your vessel? I could order the correct part and have the system back to original.
Thanks a billion :)