I was in the Ely HQ gastropub yesterday, to test whether it is actually a pub, since it has always seemed very restauranty to me. Anyway, they had no problem with me just buying a round of drinks at the bar and nothing else, so I was pleased with that.
However, they used to do O'Hara's on draught, and I saw recently that they'd switched to Porterhouse Plain. The stout taps were unmarked and when I asked what was in them I was told, with regret, that it was Guinness because that's what customers demanded and they reluctantly made the switch.
I'm guessing you could get into trouble with Diageo for serving Guinness from unmarked taps.
I'm taking all three Ely branches off the pub list -- but if anyone does happen to be in any of them (they are nice for food and wine) and does see Irish craft beer, let me know and I'll reinstate.