OK Mark- thanks for that.
It looks like discounted fares on that line only go as far as Gorey for the moment. I don't mind paying €22.50, but if I could get it cheaper I would.
There's something weird about the pricing on that link you sent. They say that a normal day return Gorey-Dublin is €16.80, yet if I ask it for a single for that route it tells me the price is €16.80. A single is the same price as a day return . . . now if I was a customer looking at their booking engine, there is nothing to tell me that I can get a day return for the same price. They should really be telling people about these fares on the booking page (in my opinion).