William Holliday and Constance Ivy Merritt are my paternal grandparents. They got married in Brighton in 1902. On their Marriage Certificate my grandmother's address is shown as West Blatchington - and in the 1901 census there is in fact a family of Merritt's living there! But not my grandmother, or living elsewhere in Sussex or anywhere in England in 1901! Her husband's entries in their family bible gives her DOB as 20th June 1881. That may be so, but she is not in the civil records under that date.
Conjecture - perhaps she was illegitimate ( a word not used these days) and Merritt was from her mother's subsequent marriage, and which new surname she inherited? If so, under what name was her birth registered? The clue is perhaps in her first two names: Constance Ivy. Has anyone come across this combination of names of someone born or living in Sussex prior to 1901?
