I agree that Sarah Grant FRENCH is likely to be Sarah Anne FRENCH, and that she may well have changed her middle name to Grant, also adding Grant to her father's name, for reasons only known to herself.
There do seem to be some rats smelling in this story - if indeed her parents are Francis FRENCH and Elizabeth nee SMITHER(S) and it does seem likely that they were, Francis FRENCH had not died at the time of Sarah's marriage to Frederick William CHAPPELL, and neither was he a shoemaker. Francis was alive at the time of the 1911 census, where he is recorded as being a widower age 76, living with his housekeeper in Monkton, Pembrokeshire. His occupation (as before) being recorded as a gardener.
I don't know whether Sarah's mother was alive at the time of Sarah's marriage, but she certainly had been at the time of the 1881 census nearly 7 months beforehand.
Was there a falling out between Sarah and one or both of her parents, meaning that she moved to Bristol to become a live-in servant, possibly having little if anything to do with them from that time onwards?