For Dave182 and others, if I may assist in putting to bed the confusion over the shades of tan / orange / "golden brown".
There were basically four shades, two being only an irrelevantly tiny bit different.
A. Original from 1962: unchanged on anything at all, bar brand new 071s, until the late 1970s.
B. Exceptionally slightly more orange version of the above, applied to everything painted from maybe about 1980 until the early 90s.
C. Distinctly, but only slightly more orange, applied to anything painted after about 1990.
D. A very much browner shade - more an orangey-brown than "orange with a brownish tint". This was on newly delivered 071s only: this colour was never used in Inchicore. It came about quite simply because GM painted them the wrong shade in Illinois. The CIE logos were non-standard too; all white, different font, larger roundel size. All 071s with this logo must by default have this one-off light brown, and all "standard orange" must by default have standard logos - if accuracy is desired.
Fading did play a part too. If you see a newly painted "E" class, say, or a tin van, in 1966, it looks just as bright orange as a Mk 2 in 1980. But as this colour faded, it looked a bit browner. Thus, a newly outshopped Mk 3 in 1986 would have looked more orange than, let's say, a Dutch van sitting beside it, though painted five years earlier in the same, or nearly same, shade.
Postscript: I saw a pic which someone had photoshopped of an 071 in NCC maroon. You've no idea how well it looked!