Nail on head…
Mr. Bluesky has hit the nail on the head. I can’t find any sort of guidance on this. Also, WW2 colour photos show inconsistent use of colour for these instruments. There has to be a some sort of order a directive from the Air Ministry to cover this.
If it was a Bf109 or FW190 I’d probably have the documentation in German and English and I’d know the exact colours, the manufacturer of the paint and the shoe size of the mechanic who installed it. It seems strange that when you consider how many Spits are out there now that there seems to be comparitively little information. I have a complete set of stencils and data plates for our Zero, but am having a rough time getting the same info for a Spitfire. Or, am I just looking in the wrong places?