There is a Liza Kelly, 20, with Edward & Ellen Cavendish at Balla Corague, Ballaugh, in the 1841 census. In the 1851 census for Ballaterson, Ballaugh, Eliza Kelly is the unmarried stepdaughter of the widowed Edward, a seamstress aged 31, born Ballaugh. I don't know where she is after that. From the census info she would seem to be the illegitimate daughter of Eleanor Moughtin with a Mr Kelly, born before her 1823 marriage to Edward Cavendish. I'm assuming she wasn't the child of a previous marriage as Elinor used the name Moughtin at her marriage to Edward. Interestingly, one of the witnesses was a George Kelly - but then it's a common name.

I note the IGI entries for 'Eliza Kelly or Moughtin' are all member submissions. I would be interested to see what it actually has in the baptism register - presumably no mention of Cavendish if my above supposition is correct.