shevvy:
The Muintervarra RC parish baptismal records go back to 1816 and are available on the free site www.irishgenealogy.ie (Church Record TAB). The only William Barry baptismal record with father James Barry I found in the parish was for December 28 1823. The mother, however, was Mary Hurley. This family lived in Carravilleen townland in Kilcrohane civil parish. Kilcrohane parish is just to the southwest from Durrus parish. People from Durrus and Kilcrohane parishes would have been served by Muintervarra RC parish.
I searched for Anne Dukelow records and the only record I found was for an Anne Dukelow who was baptized in Schull parish in 1839 but this would have been a different Anne Dukelow.
Do you have any other information? Have you considered DNA testing?
Roger McDonnell