Filed (and served) as MARSHALL in the WW1 Service Records (WO 363):

Ernest Edward GREEN-MARSHALL, born Hackney, home address Canning Town.
Father: Henry James
Worked as a mail sorter at Mount Pleasant.
Joined up in May 1916, declared age 18y 11m.
Served with the RFA (Regt No 151098) until discharge in 1919.

Anc****y, MAR, pages 12041-12081