.... he may have been originally a sailor by the name of Edwin Walter Clark(e) born 1848 hence why ? the name change.
For two good possible reasons, from what we have seen here:
Deserted the Navy?
Likely still married to Elizabeth Thorn?
Remember, his death reg in 1924 gave good detail on his parents, even though the surname used was McGaughie. However, his father was showing as John Clark McGaughey and mother Lydia Wells.
Have you looked at Edwin's 1921 census entry? Just wondering if anything new showed for his birth place on this.
Monica