Soldiers Died in the Great War states that he was born and enlisted in Sunderland and resided in Monkwearmouth.
He is remembered in Sunderland on S140.048 Part 2 page 38 and in the D.L.I. Book of Remembrance page 153.
The name "W. Foster" also occurs in other places, but there are other people of the same name to whom this could refer.