I'm seeking opinions on the colours of the above. For a time it was speculated that at least one - D3459 - had Nivo diamonds. This is now discounted as Nivo would not have been available at the time (Jan/Feb 1918).
The different machines I have seen in photographs exhibit widely differing grey tones for the diamonds. It has been suggested that they may have been VB2 blue, others have speculated that they may have been a lighter blue made by adding white or battleship greyto VB2, or perhaps simply battleship grey. It is also possible that there were a number of different colours worn by different aeroplanes.
Some of the photographs show a marked matt finish to the diamonds, in contrast to the semi-glossy PC10.
Have there been any recent revelations or new theories that I've missed to pin down this colour or colours?
Your question is a very good one, and one which I think is very difficult to answer. I am not aware of any current theories about the colours. The coloured drawings you have posted show some very reasonable possibilities. It's such a shame that we will probably never know. I am sure that Gerald Muir (who I bought one of my photo collections from) would have had either an opinion on or had asked someone who had first hand knowledge about the colour schemes. I tried to ask him as many questions as I could during the few visits I had with him, but I did not get very much information out of him at all unfortunately. He knew virtually every one of those 5,000 or so photos, and could tell the story behind almost every one of them.