Pam,
Catharine is my only known connection to the Kerruish's. I don't know of any siblings, cousins etc that is why I want to establish her parents.
Do you have a copy of John Williams marriage certificate and have you found him on the LDS UK 1881 census CD's. These should provide some very useful info. to help your search.
For further info. on the Kerruish's etc I cannot recommend Frances Coakley's website high enough.

Roy