Sustainability could be a problem on the SNN-BIQ. I have travelled DUB-BIQ twice now in the month of September, onece last year and once this year. Last year it was a 732 service and it was hard enough to fill that, this year with the 738 it was a group of 20 of us plus the same amount of annoying Spanish teenagers (separate groups!) and still there was plenty of seats left. Taking into account the presence of two large-ish groups, individuals/families were few and far between. Perhaps we can count on the new surfing culture thats becoming increasingly popular in Ireland particularly out west. Biarritz/Bayonne/Anglet is a lovely region and it is only 2hrs to Lourdes on the train (done it) and its pretty convenient. And what about frenchies coming over here?
BTW on the subject of Lourdes, DUB/SNN-Pau 3x weekly during the summer would surely be a winner, no? Much closer than Biarritz and is closer to Pyrenees resorts for skiing not to mention the area being popular with walkers too.