Years ago, someone told me they heard an audio recording of C.S. Lewis, and were surprised to hear that he had a neutral 'Oxbridge' accent. They'd been expecting him to sound like a stereotypical Irish grandfather or something.
He, as well as Wilde before him, were ethnically (or at least genetically) Irish but of an Anglicized Protestant Elite? Or were they descendants of colonizing Protestant Englishmen? Or would they have picked up 'Oxbridge' accents in the years prior to their respective rises to prominence in the environs of London and Oxford?
Are there any Irish Protestants left who sound more English than Irish?
I've never understood how this played out. The religious and ethnic history of Ireland is more confusing to me than that of the Balkans!
Rather like an English middle class educated person he would have been "above" accent. An educated middle class Irishman of his time would certainly have sounded English to most people's ears. They would have been "English" at home, no matter what their ethnology. Rather like in the rest of the UK, a regional accent would have been regarded as indicative of not being educated. Even in our modern age I have worked with educated middle class Irish people who spoke with a neutral "English" accent, in the same way that I have worked with and met people from all over the UK who have no regional accent. The Irish officer of the British army Lord Gort speaking here, https://www.youtube.com/watch?v=9IybGCgOJxM for example, was Irish, but brought up in County Durham; his voice is entirely RP with no trace of Irishness or County Durham in his vpoice. It isn't as common as earlier, but is certainly still common in the Irish upper classes.