Hi Jean-Francois, I hate to see your question go unanswered.
I have had a look, as you probably know it is not easy to research in Ireland.
'Power' was a relatively common surname, as no doubt you know. They were an important family once but remained staunchly Catholic and were therefore subject to the land divisions and inheritance restrictions placed on these families.
I have a few surnamed Power in my tree. I have others in Cloyne, with different surnames. Unfortunately I have not located de la Roche. I am looking for De Lacey not too far away, myself.
If I come across this surname I will let you know.
