I'm not a member of the Western Front Association, but I think with the help of a record on Ancestry it is possible to work out who the CWGC record refers to.
In "UK, Soldiers Died in the Great War, 1914-1919" there is the following record (Ancestry doesn't have images from that record set, so it is just a transcription):
Name Thomas Westfall
Birth Place Stoke Newington, Middx.
Residence Stoke Newington, Middx.
Death Date 19 Mar 1915
Death Place France and Flanders
Enlistment Place London
Rank Pioneer
Regiment Royal Engineers
Regimental Number 26672
Type of Casualty Killed in action
Theatre of War Western European Theatre
Comments 11Th Field Coy., R.E.
Given his name and birth place from Ancestry and his mother's initials from the CWGC, I think this is him in the 1901 census - https://www.familysearch.org/ark:/61903/1:1:X98N-GKZ.