This was quiet common in the 80's, eg one bought a house at Plot 3, X estate, now known as 23, The Green, X estate etc.
From a legal and title deeds perspective, keep the letter you just got from the council confirming the name change - it will save you c. €150.00 when you re-mortgage or resell in future.
Otherwise I would just inform the lender that your correspondence address has been changed (and hopefully they will update their system). The deeds department of your lender may note it on their system, or they may not, so you should quote both addresses with them in your dealing with that section in future.