Sergeant Fielder was a somewhat taciturn character who, with his wife, ran the post office and also acted as a sort-of major domo for the Head Master on ceremonial occasions. He also, I believe, used to distribute mail around the campus.
Sergeant Usher ('Tush') was a more outgoing and cheerful type, who took lunch parades and punishment drills.
One of those two used to ring the bell for reveille, etc.
The other two ex-Service types were the Corps Sergeant-Major (Carter) and the Band Master (Stagg). All four wore uniforms, but of different styles - presumably to meet their own specifications!
David
