Hello Frances.

I think I figured out Margaret's fate. When her husband William died in 1780, she was left with 3 children ages 1 to 5 (John b. 1775, Thomas b. 1777, and William b. 1779) and one she was carrying (Elizabeth b. 1781). My thinking was she probably remarried. I found a marriage of Margaret Corkill (widow) to John Corlet on 21 Jan 1784 in Braddan. I then found a Margaret Corlet (with husband listed as John Corlet) burial 13 Nov 1806 in Ballaugh and a Margaret Corlet burial 11 Apr 1826, Braddan (estimated birth year 1743, which wass the same birth year as her first husband William Corkill (d 1780). Not sure which one is more convincing.