I don’t know if this is obvious or well-known to 8mm Lebel collectors, but I just came across a great French website devoted to 8mm Lebel catrtridges: www.8lebel.org It is in French, but use a Google translator.
Some good info - but no mention of British manufacture by Kynoch Ltd, Kings Norton Metal Company, Birmingham Metal & Munitions. Aerators Ltd, and Greenwood & Batley.
The text of this site is a copy, word by word, of the chapter about French Lebel ctges of the book of Jacques Barlerin : “les cartouches militaires francaises”.
To get info about 8 mm Lebel of foreign manufacture (Italian, British, German, US, Vietnamese and so on) try to find the origial book.
Actually there is John, but no illustrations other than a post WWI kynoch packet. I think I shall send them photos of the the Aerators, BMM Co., etc rounds.