This is a very long shot, but I wonder does anyone remember a series of books, either History or English text books from primary school in the 1980s / 1990s which had Irish folk tales in them. I seem to remember The Salmon of Knowledge in particular. My brother asked me earlier and now it's annoying me that I can't remember.
Also looking for the title of an English book from 5th class, narrow book, I seem to recall, which had a story called "Strawberry Jam" in it, about a mouse tasting freshly- made jam.