Thanks Paul, onboard my boat a couple of days ago I'd made a note to try to find the meaning of the word "Hauptschalter," and so your explanation has been very helpful. Thanks again.
Like Fenders, I cannot recall having ever seen the green lights he refers to illuminated, but then half of the green lights (all those in the left column) on the panel itself don't come on when the respective switch is operated. It's probably something quite simple, but so long as the switch has done what is needed I can live without the green indicater which is only telling me that the position of the switch which I can see clearly enough anyway, is now in the on position.