The check in colleague indicated that we could have done exactly that, he said that as business class passengers we weren't limited to 3 hours in the lounge like the pay to access customers. We took a taxi to Swords ( was only a few euro each way) to spend a few hours there instead though - there's a Wetherspoons there for a reasonable breakfast, a castle that's free to access and wander around, and a decent sized shopping mall with plenty of food options etc.