The room was far too hot, even on a cool day. The mattress was terrible. No convenient plugs next to the bed, and the bedside lamp didn't work.
The lift was broken for about 50% of our stay. The bar only serves about four cocktails (at exorbitant rates, of course), and naturally they were unable to make any more of the one we liked, as they had run out of rum(???)
The breakfast (for which they demanded a time - no idea why, as it wasn't remotely busy) was unexpectedly a cold continental one. Apparently the coffee got the memo too, as it was ice cold.
The staff were courteous, but not really in any notable way. No one asked how our stay was at checkout, so I suspect some of this will be surprising.
I'm an occasional business traveler, so I've stayed in a fair few hotels across the UK and Ireland. This was the worst.