@topsyturvvy
I find this thread so interesting as my husband of 20 years is From Dublin. He couldn't get over the fuss about schools over here to start with.
What I have noticed though which gets on my wick is how many of the Irish friends and family always insinuate how "posh" people are in England, ALWAYS making references and jokes to it. The inverse snobbery is so ironic, imagine if people spoke like that the other way round, looking down their noses at people for having humble lives.... (and they're all well educated professionals themselves)
I think some Irish people do experience 'English people' as 'posh', though -- it need not necessarily be some kind of conscious reverse snobbery or a deliberate attempt to be snide. Of course it comes from misapprehension, inexperience and misreading class signals and accents, and an element of probably colonial hangover, just as some English people think that an Irish accent automatically signals 'heavy-drinking bogger with fifteen kids, pigs in the kitchen and the parish priest on speed-dial'. (Which is frankly a lot less pleasant to be around, and which I got from a minority of people throughout my years living in England, despite the fact that I'm a vocal atheist with one child and a PhD.)
My mother who only started to visit England when DH and I started to live there, and whose previous experience of English people was a couple of visits from distant cousins and one visit to another tyrannical elderly cousin Basingstoke definitely thinks English people are 'posh'. This is based entirely erroneously on the fact that the male visiting cousin (an awful prick, and standard-issue aspirational lower-middle-class) wore driving gloves and obsessively polished his car, and his wife said 'Pardon' a lot, while the Basingstoke cousin humiliated my poor, timid, easily flustered mother for putting a milk carton on the table, rather than using a jug. The horror.
This constitutes the 'poshness' of an entire nation for my mother. 