So the old 'Network Blue' of the case had been scratched and marked quite badly. The decision was made to return to bare metal. A Rotary Sander with 180 grit paper was applied to all surfaces for as long as it bloody took to get the old paint off. The clena surface was wiped down with mineral turpentine to clean off any paint dust and oil marks and then a single coat of clear varnish was applied. A single coat still allows a small amount of moisture/oxygen through, meaning the surface will age over time to gain an interesting 'attitude' to the machine's surface.