Hi Salty,
The issue is on the accessory control panel in the cockpit rather than the engine panels. This being the one that connects to the power board using a six wire loom and is used for lighting, engine room extractor, windlass etc. I have in the interim downloaded the pdf from another post on the site which indicates the basic connections between the two boards and it seems that the loom may well be plugged into the wrong six pin socked on the power board so I will be heading back down to the dock a little later to check on this. My understanding of the system at this point is that this loom carries power and hooks up a form of can bus between the two boards, which when a specific is triggered, i.e.: the extractor fan is switched on, that the message is carried from the cockpit panel to the main power board which interprets it and switches the appropriate relay which brings the device into operation. As it it presently connected, I get no indication on the cockpit panel led's when attempting any switching, but assume that if the prior mentioned interconnection is indeed incorrect that such will occur as a result. Can only hope that no damage has occurred as a result.
I am entirely at a loss as to why the Volvo techs would have needed to mess with this aspect of the vessel at all as they were dealing strictly with mechanical issues to the best of my knowledge, unless of course they had an issue with the engine room extractor, which I am told has not worked since they finished sorting the mech repairs.
Many thanks for your input to date though...with regards, Mike.