I have a cousin who lives in Ireland but has lived in the UK and Canada. She has a hybrid accent from all places.
One annoying thing she has noticed about living in Ireland is how acceptable it is to mock posh accents. Her accent would be described as D4 and Canadian but it's not put on at all. Despite this, posh Irish accents seem to generally be the target or ridicule. She hasn't experienced this much at all while living in London and some people even complimented her accent.
It seems like a double standard because if she/posh people made fun of working class accents, it would be seen as horrible but the reverse is fine.