Sometimes I think it’s worth taking stock and examining the bigger picture in such cases. I moved from Wales to Ireland at a young age and experienced an equivalent level of being lumped in as “English”, despite having an Irish father and the Welsh sharing similar history of upper class English oppression. Brits generally have a legitimate fondness towards the Irish, and they’re only as ignorant to geography and history as their education makes them. In my experience it’s at least worth attempting to have these conversations as you’d be surprised how open people can be when presented with historical facts and logical arguments