The Sky&The Ground (South end of Main St.)may be worth checking. They certainly do Leffe and Fischer Helles and that sort of thing. Been a while since I was there, so dunno if the menu has expanded any. As tube said, Simon’s place has Dungarvan bottles, as does the Greenacres restaurant (North end of Main St).
Other than that, do what I do when home….. nearly everywhere has large bottles of Macardles (off the shelf, of course <!-- s:) --><img src="{SMILIES_PATH}/icon_smile.gif" alt="

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If yer looking for an off-licence, Pettits (St Aidans) has a fantastic range.
Edit: just saw yer last comment on Large Macs!