I'm willing to accept independent Scotland, but Wales is now too strongly tied to english, so it's not very plausible.
Scotland and Wales independent, Northern Ireland joins Republic of Ireland, possibly even Cornwall becoming independent. This leaves the block of Celtic States more evenly balanced with the power of England. They (England, Scotland, Wales, Ireland and Cornwall) come together again as a loose confederation of independent states with open borders entitled the Confederation of the Northern Islands. One variation on this is that London becomes an independent city state outside of the Confederation (to protect the status of the City of London financial area)
Wales should be independent, I have a Welsh heritage in Wales and I think 99% people speak Welsh and 1% speak English.