Living in Carrigaline, myself.
Suggest you check out the following:
(built in Carrigaline, major rivals to Redbay, both are some of the most capable heavy-weather RIBs on the market.)
(Redbay & Zodiac dealers, but can get you a Ribcraft too if you want, generally have a good selection of used boats or know of customers wishing to sell) The biggest and best engine dealer in the south too- Mercury, Evinrude, Johnson and Honda.
(RIB specialists but not as good as top two)
There usually are a few RIBs for sale at the side of the road and on the water at Cork Week, which you'll probably be at if you're into sailing anyway.
But why stay local? I went the whole way to Barnet, London for mine, there wasn't even any water there!!