Hi to everyone and thank you for your replies.
Yes, I have asked before, but I thought I might pick up some new Rootschatters by asking again!
I was unsure about the name McCaa, and when searching I try to check McCall, McGall, McGill, McCaw - what a nuisance! However, I asked on here, and some RCers have found the name McCaa in other sources and thought it may be right, so I also persevere with it. I am sure all the various permutations are the result of priests' interpretations of local accents, and the owners of the names never wrote them down anyway, so spelling would be an irrelevance to them.
Thanks for your interest.
Harlemswife