Can you clarify the name of your great-great grandmother. Was it Margaret McDonnell? I ask because I searched the free site www.irishgenealogy.ie (which has records for St. Finbars) for Margaret McDonnell and did not find the 1813 record. I even searched under John Scanlan and none of the John Scanlan records had a Margaret McDonnell. Thanks!
Could you copy and paste or attached the record you found.