Update. In the end, I sent away for the PDF of my gggg-grandmother's death certificate and that of "Agnes Ann Walter."
In the first case, I only confirmed my guess but it's always interesting to know something of "cause of death."
Agnes Ann Walter's information on her death record is inconclusive as there is no indication if she is the same as the Ann Walters born in Scotland (sometimes the "informant" is a clue)
The only possible clue, apart from the fact that the age fits, is that she did die in South Street, Louth... this is where, according to censuses, the Scottish Ann lived in 1851-71. If it is her, I wonder why all of a sudden she is Agnes Ann!
This is some of what the certificate contains:
Date and residence: 24th of July, 1875, South Street, Louth; age 87; **widow of Thomas Walter, private soldier**; cause: Ramolissment, certified by...; Informant : C or G Lamming??? present at death, South Street; Registered the 26th of July.
P.S. additional note: Maybe Charlotte Lamming, nee Dannatt (various spellings), born C. 1837 South Elkington, Lincs. (I'm always looking for potential links!!); probably not family, although the informant often is.
At this point, it should be easier to disprove she isn't the same one than prove that she is! At any rate, I am no further finding out if Ann is Caroline's mother, and if not, how she relates to Caroline (because I'm convinced she does, if only as an aunt) ! Oh well
I wish you the best of luck for your own searches!