Inside the EU, it's the shop's job to settle up with Irish Revenue, and I'd say none of them do. If they don't, then the parcel could be stopped and you'll be liable for the charge. In practice I get the impression, anecdotally, that parcels sent from inside the EU don't get the same attention as those from outside.
I'd advise asking the shop if they're sure it'll be OK to order the beer from Ireland. At least then you have comeback with them if something goes wrong.