Further to my last message:
I show a Catherine living with Charles Brew and Catherine Quayle Brew on the 1851 Isle of Man Census. It shows her as mother-in-law and a widow. It states her age as 87 therefore I assumed her date of birth as 1764. It also states her place of birth as Braddan. She is not on the 1861 census. Therefore she died between 1851 and 1861. Does that help at all in coming up with a will for her. William obviously died before 1851. I am assuming here that she is Catherine Cubbon married to William Quayle.
Is this any help?