I remember this happening once before. 771 put a Sea King into Eire at the end of a Sarop, no drama as conventions exist to cover that. They went down bird and the Sqn sent a follow up cab but without dip clearance. The military attaché made a couple of quick phone calls and it turned into a non event.
However, taking a military aircraft into a foreign country without dip clearance is technically an invasion so I can see the Irish point of view here.