My sincere apologies aghadowey for not posting the link to the census. It was 1851. I thought because it had been posted that you had seen it. I tried to post the link but with absolutely no success. Thanks Wren.
Can't see it posted on this thread but here is the link-
http://censussearchforms.nationalarchives.ie/search/cs/details.jsp?id=51407However, it looks as though you are reading it incorrectly.
The applicant (Mary Griffith aged about 10 at time of census?) was Mrs. Mary Cunningham of 142 Woodstock Road, Belfast.
Several places look to have been searched without finding the family. Pay special attention to notation lower right corner.
When the application was made (in 1920) Mary listed names of parents & siblings in order to find the census record.
Therefore Mary seems to have been living at Woodstock Road
in 1920 on the 15 September when she attempted to apply for the pension.