Dates of Epiphany and Baptism celebrations shifting in Ireland and England

In Sunday Missal approved for Ireland, England & Wales, and Scotland I found, that the Epiphany of the Lord is celebrated on 6 January in Ireland, while in England & Wales and Scotland on 8 January. The same shifting appears for the Baptism of the Lord celebration: 8 January in Ireland, 9 January in England & Wales and Scotland. What's the reason for these shifting? Can it be in order not to mix celebrations of same holidays in Church of England and in Roman Catholic Church for families with mixed confessions?