I noticed that on some photos, including my project, the antenna mast are in a different colour that the camo colours (in the temperate land scheme or in the day fighter scheme)...
Maybe a stupid question but is it possible that on some Spitfires, the antenna mast was the same colour "red brown" of the base insulator plate ?
I found this from: A Guide to Spitfire and Seafire R/T Installations, masts and aerials.
It seems the mast was of the camo colour mostly. But it might have happened it could be of a different one because of the maintenance , etc .. Also it should be kept in mind that the antenna mast and its base were attached at the end of the final assembling when the plane was already painted. So the different paint is possible IMHO.
However I would be very careful of the so-called colour images. There has been appeared many of such colourised pics recently. Although the general appearance of the camouflage colours is correct usually, the one of the details seems to be the wishful thinking of the authors only and often. The one in the shot above seems to be painted with the well-known primer named Minium used for protection and primering.
The shot of the Castle-Bromwich plant yard shows the MK.IXs with the masts of the darker tone than the OG camo spot there. However the two next ones reveal the masts being of the light tone. But the two bottom one showing the earlier variant of the Spitfire present the dark masts with their bases. So it's is your choice.
The mast bases, when unpainted, would have been a dark reddish brown colour as this was the colour of the resin in this laminate material, similar to modern Micarda. The masts were wood so there would be no reason for them to be related to the base.