I have 7 hour layover at Shannon airport en route to London from New York. I am thinking about squeezing in a visit to Bunratty Castle. I plan to take a taxi or bus (if i am lucky enough to catch one) to the castle and take a taxi back. Can anyone tell me if this is feasible? Is 2 hours enough to get through security and immigration at Shannon airport? Is it difficult to get a taxi at the Castle? Many thanks in advance for your advice.