Mine is fitted entirely on the other side of the lazarette.
Was the heater in place while the boat was actually being used for charter work? If so you could ask the charter firm whether the coding surveyors ever had anything to say about the proximity of the heater exhaust and the fuel filler cap, and could they provide you with a copy of the initial survey for the last five year period, and for the intermediate survey. Find out if you can whether the heater was fitted from new, as it's hardly likely that if fitted from new that the fitter would have made a mistake and then the coding surveyors subsequently allowed that mistake to slip by unnoticed.
As a last resort you could re-route the exhaust across to another area that does meet approval, but a bit of a pain as you would probably need a longer exhaust hose and insulation, to say nothing of a new hole for the hull fitting and the old one to block up. New exhaust hose is available through eBay at £14.95 a metre.
