Hi again,
Thanks for your explanation on Sarah. I think that would have confused me if I saw it on a certificate.

This looks like William and Sarah Barker on the 1881 census:
Address: 51 Tylefield St, Glasgow, Lanarkshire
William Barker, m, head, 33, baker, England
Sarah ", f, wife, 22, -, Glasgow, Lanarkshire
Mary ", f, dau., 9, scholar, Glasgow, Lanarkshire
Jemima ", f, dau., 7, scholar, Glasgow, Lanarkshire
Catherine ", f, dau., 4, -, Glasgow, Lanarkshire
Janet ", f, dau., 3, -, Glasgow, Lanarkshire
Sarah Irvine, f, mother-in-law, 56, retired weaver, Ireland
Looking at the IGI shows that Mary and Jemima were to a first marriage of William's (to Elizabeth McRobert). A free search on ScotlandsPeople shows he married Sarah Irvine in 1880.

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