Apart from all this hi-falutin stuff, are you aware that, of the four major Dublin railway stations, Tara St. is the only one without a public toilet. Think about it. You could have to wait till Greystones or Malahide.
I have documented the comparison with Pearse here
There used to be a toilet there when I was going to school, but the convenience lost out to commercial interests.
On a slightly different tack, the UB buildings are quite harmonious from one angle