I spotted the obvious and was educated as to the not so obvious (to some).
I knew that ‘Chapel’ was not the Irish translation of ‘Chapel’ – ‘Séipéal is the correct word.
I also knew that adjectives generally follow the noun in Irish but learnt that ‘sean’ (as in ‘old’) is one of the exceptions.
Oldchapel is translated as ‘An Seanséipéal’ on logainm.ie.
How ‘Chapel Sean’ got through Cork County Council and/or N.R.A.? Your guess is as good as mine.