Jim I would be tempted to present your case to the under writer. Skip the broker and surveyor and have a discussion with them. Give them all the info and be sure to include the builders info. Have the builder write down and send you the info given over the phone. I have found the underwriters to be a bit more willing to negotiate through problems if they are presented with sound information. Like that of a builder not to say builders are always up to snuff but. Now after saying this if you are not happy with the installation any way this might be a good time to change it. So if the underwriter agrees then running a new line to an appliance or two is not a big deal. As for a locker you might be able to just section off the existing space. Then vent it to the outside of the helm station. Personally I would choose to change the system and involve the insurance company at this stage. Make them accountable or liable for the system they want changed <grin>. I made a fuel locker that is fastened to the aft deck. Vents overboard out the hull. Holds two 20lb propane bottles, 1 X 5 gallon gas 1 X 5 gallon diesel, two cycle oil etc. All the propane lines start there etc. Ply box epoxy coated with paint over and a hinged top. Easy. But I have an old fishboat so not a yacht. Willy Invader no 1 39 kishi conversion