connecting a 12V source to the warning lamp on the alternator.... and it pinged into life!
So... despite a dunking, everything on the engine is working just fine!
Just got to sort out the wiring from the alternator to the warning lamp, as that is obviously the problem, and all will be fine.
Along the way, i've put the final matt coat of varnish on all down the passageway..... so that's it.... the last of the last coats in the main saloon is done!!!!!!
(actually, i've a few draw fronts to do, but pretending they don't count)