Looking back at some of your posts Anne, I see that you refer to the Stantons. Be a little careful as the surname is interchangeable with Staunton.
According to the BMD & Census records, Mary W O'Malley's parents (Patrick & Catherine) were STAUNTON. And this corroborates with all the parish records I've been able to find.
It was said that Patrick's brother Thomas (my great grandfather) & spouse Honor changed their name to STANTON, apparently to avoid confusion. [there is some debate as to exactly why].
The birth records of the children of Patrick Staunton & Winifred Ruane's (ie Thomas, Patrick etc) show that some of them are listed as Staunton and others as Stanton. So apart from any formal change, it was very interchangeable anway - presumably a function of the accent, the priest's hearing etc. Note that all the children used the name STAUNTON, but only Thomas P changed to STANTON.