I searched manually on the National Archives for nearby numbers, and made this list:
74956 Bamford, Henry J.          Corporal
74957 Fowles, Arthur             Corporal Mechanic
74958 Melville, Frederick E.     Mechanist Corporal
74959 Thompson, William E.       Mechanist Serjeant
74960 Mahoney, Phillip           Mechanist Corporal
74961 Keeling, William E.        Corporal
74962 Wansbrough, Reginald       Corporal
74964 Drew, Oswald F.J.          Corporal
74965 Braun, George I.           Corporal
74966 Edmonds, Frederick P.O.    Mechanic Corporal ... Serjeant
74967 Dallison, Robert Victor    Corporal
74968 Salter, Henry C.           Corporal
74970 Pruen, E. Tristram         Corporal
74971 Agg, Albert J.             Corporal 2nd
74972 Hunter, George             Sapper
74973 Dougherty, Alfred          Lance Corporal
You mentioned 74969, which I couldn't find.
Do you have the name/rank for that man?
74963 is also missing from my list.
W E Thompson is William E. Thompson.
A Sergeant Ted Thompson appears frequently in my grandfather's WWI photos, so I think that the E. stands for Edward.