I went to family search.org and found a death for
Harriet Annie Lock
Victoria, BC
b. 19 May 1869, Birmingham, England
d. 15 Oct 1956, age 87 years
spouse - Walter Edwin Lock
parents - Edwin Downton and Ann Porter
went to Free BMD
marriage Quarter Jun 1909
Lock, Walter Edwin
Underwood, Ethel
Cheltenham, vol 6a, page 916
marriage Quarter Sep 1918
Harriet A. Downton
Walter E Lock
Cheltenham, vol 6a, page 1046
I couln't find a death for Ethel before the marriage to Harriet but it is possible that he would have remarried soon after a death if he had small children.