Hi Diana
I've been investigating your family but so far I can't find Catherine with that surname.
I downloaded William's death cert of 1861 but it only gives Jean/Jane Little as his wife . This is very unlucky as many Death certs give the names of all spouses

I also note that on the 1851, William was born Glencairn, circa 1782. The only Catherine/Katherine/alts coming up for there at the approx date was a Kathrin Hairstons. Parents - Charles Hairstons and Janet Copland. This, of course, might well not be her and she may have been born in Sanquhar or elsewhere

There are 7 Kathrines (alts) coming up for Sanquhar 1780 +/- 10.
Would the name of Catherine and William's children in birth order help. They may have followed the traditional naming conventions:
1st son - after man's father
2n son - after woman's father
1st daughter - after woman's mother
2nd daughter - after man's mother
etc.
Gadget