Geography

In series 1 episode 13 (Greetings Stout Yeoman) the Riley's Stout rep states that the Guvnor's pub will be the first pub outside of the Republic of Ireland to sell his brew on tap.
He then calls the stout "The Cream Of Belfast".
As Belfast isn't in the ROI, why would he say such a thing?
Does whoever wrote those particular lines not know the difference between Northern Ireland which is British and Southern Ireland which is Irish?



I was walking down the skyway my way...