Darren,
There seems to be an issue as to what the color should be if any, of the armor plate on the top of the engine compartment. I looked at Antoni's referred to site, and those pictures certainly look that of a restored aircraft. Restorations have a nasty habit of being wrong, as they're all to often based on inconsistent data, incorrect interpretations of B&W/Sepia photographs, and old war memories.
There is one picture of a completely stripped Spitfire, but that doesn't mean that it went back into service that way, as it still needed to have all its markings painted on, so they could have painted that anti glare panel then. There is also a picture showing that panel to be quite a bit darker, and very close to the panel color of the camo painted Spitfire in the foreground of that photograph.
You should also take into consideration that the purpose of painting that area from the nose to the windscreen a dark color, was to help kill the glare from the sun that the pilot had to deal with. I find it hard to believe that they wouldn't have addressed that issue, as the pilot or pilots would have certainly addressed it.
Your build is coming along quite well. Nice job on the cockpit. From what I see on my monitor, the interior Green could be a little more blue, but that doesn't mean that your actual color isn't correct. Once the fuselage is closed up, one sees very little of the cockpit, and it's always in a shadow. Looking forward to seeing your Mk 1Xc with some paint on it.
Joel