Memory could be faulty, but I believe the aforementioned James Sims mentions 2nd Bn dying their lanyards yellow with mepacrine.
https://www.google.co.uk/amp/s/serge...e-chasers/amp/
A quick google rather than search for the book:
2nd Parachute Battalion’s first Commanding Officer, Lt. Col. Edwin Flavell, gave each of his officers a bright yellow lanyard to wear on the left shoulder, to distinguish them from officers of the other two battalions. The “other ranks” (enlisted personnel) decided they wanted to wear the yellow lanyard, as well. However, they had to make their own, which required a certain amount of improvisation and ingenuity.
The lanyards were made by cutting a length of rigging line, made of white silk or nylon, from a parachute after a training jump. This cord was braided or tied into a lanyard; those unskilled in making it themselves begged help from friends.
The most ingenious part of the process was dying the lanyard. Troops sent to the tropics were ordered to take Mepacrine, also known as Atabrine, a bright yellow medicine intended to fight malaria. Continued use of this drug was known to turn the skin and eyes yellow; therefore, it was seen by the troops as a logical dye. Mepacrine pills were acquired, then ground up and dissolved in water to turn the white lanyards a deep yellow or golden color.