More on "'Sé do bheatha" - literally: "It is your life" and is used in both Gaeilge and Gaidhlig. It can mean both "Hail" and "You are welcome" (and in Gaidhlig, "You're welcome" as in a response to "Thanks") depending on dialect and intent.

Both Dord and Durd are "correct" in that both are used in both Gaelics. Likely that dord would be the more prevalent form in Ireland.