I suspect the reason that they only attend 1 out of 4 mountain jobs is more to do with lack of NVG capability as most calls for missing walkers come late in the day.
Also, regardless of helicopter size, if the mountain is in cloud (as they mostly are in Ireland) you can’t achieve terribly much. Small helicopters possess no greater magical skills than big ones.
It sounds like Irish MR are filled with as many helicopter “experts” as UK MR