

Looking at https://www.geni.com/merge/view?revision_id=80694628870 and https://www.geni.com/revisions/profile/6000000178141284869?rev_id=80694628870, the death date of 20/11/1976 and death location of Chesterfield, Derbyshire, Rngland was entered by Private User
The only source on the profile is her birth record.