Ah, it seems Wallis Darlington did die in 1945 and Matilda in 1957:
https://irelandandthegreatwarblog.wordpress.com/2017/06/12/corporal-wallis-darlington/Also, mention of a son, Ralph, born 1912. Looks to have married in Dublin in 1939, in Roman Catholic church. Ralph appears on an Ancestry tree. Wallace/Wallis and Matilda appear in several trees.
Headstone for Walter and Matilda says 'our dear father' and 'our dear mother', possibly implying more than one surviving child at 1957 (or could just be that as Ralph was married, he was including his wife in 'our').