How about a full balkanization?
NATIONS OF THE BRITISH ISLES:
North (Gaelic) Scotland
South Scotland
Wales
Cumberland
Northumbria (Northumberland, Durham and Westmorland.)
United Kingdom of the Roses (Yorkshire, Lancashire, Derbyshire and Notinghamshire.)
Cornwall and Scilly Isles
South West England (Devon, Somersett, Dorset, Hampshire, Wiltshire and Gloucestershire.)
Soth East England (Everywhere else.)