Thanks Francis! In my posting on 25 October, I was hoping, after reading your transcription of Isabel Corlett's 1799 will, that Isabel Kneal who had an illegit daughter Jane by Irish Man John Darcy, might turn out to be the Isabel Corlett of the above will, having married a John? Corlett sometime after March 1756.
(Jane Darcy married and had a daughter Jane Cavendish, bpt in Kirk Michael in 1781.)

The IGI didn't help but there was the promise of register transcriptions!

And there she is! The first Isabel in the list, 8th marriage down:

14 Jan 1758 CORLETT John, weaver, and KNEALE Isabel , both of this parish,
witnesses thomas corlett & chas casement clothier

So that sorts that one out. I'm tickled pink to find out what happened to Isabel as she is my direct ancestor and also the ancestor of all the American Manx Cavendishes. Thank you very much, Francis!

So, next I find out how old she was when she died (presumably 1799 - no burial in Brian's index) to work out her birth date, then I find her baptism and her parents.....