Gordon, I am an American hobbyist whose curiosity was piqued by your inquiry. A couple of questions and/or observations:
Are you sure about the spelling of the family name? As did Janice, I checked the CWGC database and found a listing for an Alexander Turish, Irish Guards, son of James C. and Elizabeth Turish, Castlederg.
If this is the same man, are you sure of his date of death/age? The CWGC listing shows DOD 23 May 1940, and age as 25.
I searched the database for a W. J. Smyth, and the only listing with DOD during WWII was this:
Name: SMYTH, WILLIAM JOHN Initials: W J Nationality: United Kingdom Rank: Civilian Regiment/Service: Civilian War Dead Age: 22 Date of Death: 16/04/1941 Additional information: Son of James and Sarah Smyth, of 63 Malvern Street. Died at Percy Street. Casualty Type: Civilian War Dead Reporting Authority: BELFAST, COUNTY BOROUGH, N. IRELAND
Hope some of this info is useful, and does not serve to further "muddy your waters".