So I am northern Italian, which is already a bit of a strange accent for Italy (long vowels, many consonants fall, etc.), then I moved to England and lived first in Yorkshire where my best friend is from, and then in Oxford, but with two Irishmen and a Scot in the house, and then I met my future husband who is a Welshman raised in Norfolk. The result? After four years in England, I developed what has been recently defined by a friend of mine a ‘Eurotrash’ accent, with bits of Irish, Northern, Scot pronunciation scattered here and there across my fake-RP.
That said, I love English Northern pronunciation and every day that passes I am more and more tempted to ditch the stupid RP and just go for my northern mash!