Apparently ( from Wiki ) this happened to be a bone of contention for a good long while .
The government of England specifically chose to refer to Ireland as "Eire" in order to undermine the claim of the 26 counties to the 6 ( the whole Island being Ireland )
While Dev had wanted the country to be Éire ( 1937 - 1948 ), most people at the time recognised the international brand of Ireland was a better bet.
While these issues have been resolved with the good Friday agreement, a lot of the English press still have guidelines which specify that they call Ireland , " Southern Ireland , or Eire , or the Republic of Ireland "
Moot point , there's the Peoples Republic of Cork, and the rest of Ireland , The united Kingdoms feelings on the matter don't count in the end .