Sergeant in Royal Army Medical Corps

[clwech]

Hi, my relative joined the RAMC in 1915 & his marriage certificate in Dec 1915 has his rank as 'Sergt Major'.  He was admitted to No2 General Hospital @ Le Harve in July 1916 & again was recorded as 'S.M' but in the 95FA Battalion War Diary he was recorded as Acting Sergt Major.  He moved to 10 FA & on 21 November 1917 the diary says "Sgt H ... appointed AS Sgt".  A newspaper report also says he was Bearer Sergeant.  

Please can someone explain the various sergeants.

many thanks 

clwech

Edited 8 June , 2019 by clwech