From T1 domestic there is - you go up the escalators almost opposite the executive lounge - but pax arriving from RoI are required to go through a security check to get airside, so everyone arriving from DUB goes through the customs check-point upstairs and into the domestic bag reclaim hall. This is why there's a funny little automated gate and a bored BAA bloke separating the bag reclaim area from the gates.

RoI pax therefore have to exit at the same place as UK arrivals but the FCC is signposted - take a sharp left then left again. You go down a few stairs and into the left hand side of the T1 domestic security check point where I think you get priority in the queue. Then go back towards the gates and up the escalators opposite the exec club.

However, I don't know what the score is with boarding passes - they might let you through with the ticket since you're a connecting pax, but I don't know.