Isabella's maiden name is Mckenzie so I don't think that is her in the prison register. Although the birth date and place of birth seems correct.
Thank you for the place of births. The read so clearly when someone has suggested what they could be and Dunover & Ballylimp tie in with my suspicions.
Her sister who moved to America put down St. Andrews county Down as place of birth and another part of the family is from Ballywalter, so both Dunover and Ballylimp make sense.
Many thanks.