Hello again Chris. From the research I've done, one of the sources re wiring comes from a Lance Corporal Vic Cole who was a signaller with the 7th Queen's Own(Royal West Kents) during WW1. He states that the Royal Engineers' Signal Company always used superior, thicker cable than theirs. In one case he describes three wires: "Our thin black D3 cable, a thicker red cable for artillery observation and a thick black cable of the Royal Engineers." So was D3 black or red? I know the originals were shellac black so is that the confusion.
As regards "Signalese", like you say there was so many words added to the English language from the soldiers' time in the trenches, apart from their own internal language e.g. Ack-ack (Phonetic letter "a") for anti aircraft fire; Ack emma (a.m.); pip emma (p.m.); emma gee (machine gun); toc emma (trench mortar) amongst many more you probably know, and that's apart from the corruption of French and Hindustani words into our language that the normal Tommy couldn't pronounce properly!
Thanks again,
Terry