As I'm Irish, I thought I'd introduce the idea of Hiberno-English to the thread (Joyce, Beckett, Yeats, et all). I speak and write British English, have travelled a lot and have lived and worked in the UK and elsewhere in Europe. However, Irish friends refer to what they say is a pronounced "English" (rather than British) accent, while some of my British friends have alluded to an accent which they have termed "educated Irish".
Regional accents used to be very strong in Ireland (think of the "Norn Iron" conflict, or how Ian Paisley/Gerry Adams speak, to get that flavour), while linguistic scholars cite the far south Munster accent as quite similar (they think) to what 16th-17th century English might have sounded like (yes, we are back to what TEG wrote about historical vowel changes). Class is possibly a somewhat stronger indicator of accent than was the case in earlier times, when geography prevailed.
Cheers.