The will has always troubled me in that, though many of the details fit with the family of John Garrett and Catherine Tear, there are some parts that don't quite gel. I can't find a christening for son John for example. Then there's daughter Mary. I thought she might be Mary Radcliffe, her daughter by marriage to Stephen Radcliffe but if this Mary married John Gawne then she had quite a brood of children of which no mention is made in the will.
I don't think I can help you very much here at the moment. All I can say is that a] that's not the will of Catherine Garrett als Radcliffe als Tear; b] it is but she has for whatever reason not made mention of all of her grandchildren or c] that's not your Esther.
I wish I could help. I did check in "Andreas" by Sally McCambridge. It mentions John Camaish, son of Matthias and Esther but that's all. It doesn't even say that she was Esther Garrett.
If she's the Esther Camaish who died 1837 Andreas aged 70 that gives you 1767.
The death for a Matthias 1825 doesn't help as no age is given.
So really I've not been much help.............
Jane