Here is some more info. Sorry to disappoint you Skippy, but I knew it was a Cockerel but I did not want to go back upstairs at the time.
In Para 59 you will find reference to "illiterates", this should now read "learning difficulties". The ID labels were very heavily used in Burma where there were a lot of East and West African troops handling SAA, particularly when they were hunting round stacks in the dark, with their little right angle torches, with the red filter fitted. Similarly, after the war there was a lot of sorting to be done in Europe, using a lot of 'displaced persons (DPs)', many of whom became 'European Voluntary Workers (EVWs) and worked in our Ammunition Depots at home and overseas.
The label I have put in is a GEG 10 label with Army and RAF differential and you can see from Reccetroopers labels that they are Army.
The labels went up to 15 although I can only remember 13. There were also associated Fire Risk signs which went on the ends of the stacks or outside buildings. I did not put these in because they are not on packages.
Things changed a bit in the mid 1950s with the introduction of less Groups, 1 to 6 and Metallic powders, with Fire Risk signs X,Y,Z,and ZZ and these did go on the packages.
In the mid 1960s things got more international and the Orange Labels with the Bursting Bomb symbol came into use.