The freezer paper thing has been befuddling me also I haven't sen it anywhere but it must be around somewhere. Maybe Lidl or Aldi or the really big Tescos'.
It's just plastic-coated paper used to wrap food before it's frozen. It comes on a roll just like aluminum foil. The plastic coating is very thin but, when used for stenciling (the most common crafty use) the plastic keeps the ink from permeating the paper. It's handy and disposable, so very popular!
And hi! I'm another crafter here in Ireland, but I'm in Cork. I've found very few craft-y places so far (Only lived here for 3 months, and I'm from Los Angeles, so it's a biiiig difference!) so I'll be keeping my eye on this thread.
To give what little info I DO have about crafting in Cork: there's a store called Vibes 'n' Scribes: it's mostly used books and music, but their larger branch, on Leavitt's Quay (I think) has a craft section with some lovely yarn, craft books, beads, etc. I didn't actually spend too much time there 'cause I was afraid of spending waaaay too much if I stayed to browse! There's also a pocket-sized craft store in a little nook across the way from Tesco in City Centre, but it's quite small and seems more embroidery-focused, though I did buy a crochet hook there. Nice ladies behind the counter though!