I've been looking again at Frances' summary of the Will of Isabel Corlett (Kneale) dated 1799:

www.isle-of-man.com/manxnotebook/famhist/wills/le1698.htm
Summary of Wills - Lezayre 1698-1799
Year Par court Name als My Notes
1799 A 77 CORLETT Isabel widow:
son John Corlet, gdau Isabel Corlet;
3 daus: Margery wife of John Crow, son in law John Crow, grandson John Crow,
Catharine wife of Philip Garret,
Mary wife of James Skillicorn (exec);
gdau Jane Cavendish;

Can anyone point me in the direction of a burial for Isabel? There doesn't seem to be a suitable one on BL's microsite. A complication is that there were 2 Isabel Kneales who married John Corletts in Lezayre around the same time:

John Corlet mar. Isabel Kneal 7 Oct 1755 Lezayre [familysearch]
John Corlet mar. Isabel Kneal 7 Oct 1755 Lezayre [F. Coakley Mx Ntbk]
John Corlet mar. Isabel Kneal single 14 Jan 1758 Lezayre [familysearch]
John Corlett weaver mar. Isabel Kneale botp 14 Jan 1758 Lezayre [F. Coakley Mx Ntbk]

(I'm assuming the correct marriage is the 1758 one as Isabel Kneal had an illegitimate daughter in 1756.)