Identify a ghost story about a mirror in a hotel room, possibly in Ireland

As a child in Britain in the 1980s I remember reading a ghost story in a (1970s?) British compilation which went roughly like this:

• It is set in Ireland, or at least mentions an Irish city.


• The protagonist misses a ferry, and has to stay at a full hotel.


• There is one room, but the hotel keeper is reluctant to give it to him.


• The room contains a mirror.


• The protagonist falls asleep, but wakes during the night.


• He goes to the mirror. There is something wrong about his reflected image. It may be something to do with condensation or drops of water on the glass.


• ??? [I do not recall what happens; either I did not understand, or I skipped it because I was scared.]


• Much later, the protagonist is back in his own house. He passes a mirror, and notices that there are drops of water on it. [I did not understand the significance.]

The compilation may have been by Aidan Chambers; at any rate, it was 1960s-70s and of the same sort. I don't believe the story can be hopelessly obscure, but Google has not given the remotest clue. I just want to know what the story was actually about.