Very interesting, L-B, I had always thought the unique service number came in during the war, but happy to be corrected. I am sending you a PM with my email address as I would appreciate a copy of the article you refer to. I have been in touch with my medal collecting chum and he tells me he has a fair sized collection of WW1 medals to recipients with 3 digit numbers, including Z-204 to the RFC and 800 to the RAF. He also has quite a few "number ones" including to the RA, RAMC, Rifle Brigade and The Queens,as well as several Indian Army units.