Where do all other census records record her as being born?
It's not a place which could easily be misheard unless it's somewhere in Sunderland rather than Sutherland?
I think a reply from SP may answer some questions even if it means yet another email to NRS.
Annie
The census records I have (ages are a bit wonky, but the kids add up) show her in:
1841: Where born: Scotland, out of county (they were living in Kelso, Roxburghshire at the time)
James Wilson 28
Isabella Wilson 27
Ellenor Wilson 4
Robert Wilson 1
1851: Where born: Sprouston, Roxburghshire (this one is the anomaly; Sprouston is where James was born. The children all add up though: the two that were listed in the 1841 census, plus three more and an extra "orphan".
James Wilson 36
Isabel Wilson 35
Ealanor B Wilson 12
Robert Wilson 10
Margaret Wilson 7
Mary Anne Wilson 5
William Wilson 2
Elisabeth Stewart 7
1861: "Where born" is listed as "NK"...I presume "not known" (again, children still at home add up)
James Wilson 50
Isabel Wilson 48
William J Wilson 12
Isabel Wilson 6
1871: Where born: Sutherlandshire, Parish NK (last remaining daughter still at home.)
James Welson 61
Isabella Welson 59
Isabella Welson 16
I've found William / Eleanor's other children, and reference in a number of undocumented sources to an Isabella being among their number. All the children were born up north (William himself was from Sprouston, and Eleanor from Northumberland); the ones on either side of Isabella's DOB were born in Sutherlandshire (including Mary Ann and William, who remained unmarried and lived with the parents as adults).
Maybe I'm filling in too many blanks...but my gut feeling is that it adds up.
J