I've recently booked a NCL-LHR-DUB trip in CE, the difference between travelling in economy and CE was £100, for the return trip I thought this was a pretty good price and bearing in mind the lounge access before all four flights, the extra 80 TP for the trip and priority boarding, I think this is a pretty good deal. Even if the actual seat on the plane for the DUB legs isn't much different to the domestic leg, the £25 per leg makes it a good buy in my book. However on a longer flight the seating may become more of an issue but on a one hour flight it makes little difference to me.