I presume you'll need a JAA ATPL (frozen), JAA IR and I would imagine 1000 hours or so to get in the co-jo seat. That is what I was told before. But these days, with economy issues and a ridiculous amount of experienced pilots looking for work it isn't easy. I know a lot of guys back in Ireland with CPL/IR that are working in their old jobs. The SAR game is a sought after one in Ireland and chances of getting there are slim without experience.
The problem is that there are no jobs in Ireland for heli pilots because there is no industry.
Keep the dream alive though.