The Elizabeth Shimmin who married Daniel Gilmour or Gilmore does not appear in the 1851 census.
In the 1851 census a Daniel age 50 b Ireland is married to an Isabella (possibly Shimmin) 52 b German and residing at Balla Hudson cottage in Marown. One child in the census, Anne, b 1829/30 in German seems to correspond to Ann Gilmore, who was christened in German on April 25 1824, daughter of Daniel Gilmore and Isabella Shimmin.
Another, Jane b Marown 1838/39, appears to be the daughter of Daniel and Elizabeth Shimmin, and was christened on April 29 1838 in Marown.
A third, Joseph b Marown 1835/36 corresponds to Joseph who was christened in Marown on November 15 1835.
However, the census also shows a William Gilmore b German age 22. Whereas on the IGI the William Gilmour son of Elizabeth and Daniel ws christened in Marown on August 7 1845, which seems rather late.
I checked Brian's site. The Isabella in the census may to correspond to Isabella Gilmour buried in Marown on April 11 1888 aged 95 and the Daniel to Daniel Gilmour buried July 25 1867 age 70.
Finally, as the IGI has no records of a Daniel Gilmour marrying an Isabella, I wondered if Isabella and Elizabeth are the same person.

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