Nationalism of any kind whether Welsh, Scottish or English will only cause more problems, Nationalism destroyed Ireland, Germany , Italy , Spain ect. it only leads to tears in the end.
I'm afraid I don't understand that. Ireland gained its independence from the UK in, I think, 1922, but from whom did Germany, Italy and Spain gain their independence?
In fact, if I remember my history correctly, both Germany and Italy became countries due to the union of a previous collection of smaller principalities, duchies, etc in the 19th century.