This is seems so strange to people in U.S. We don't care where you went to school. But the Brits are obsessed with it. Articles on James mention where he went to school, even how much Ampleforth cost per year. Like we care. But they care in England.
http://www.theguardian.com/media/2016/feb/02/james-norton-tv-producers-also-typecast-against-posh-actors
for the most part you can't tell whether or not anyone was rich or poor growing up, unless they were really undereducated.
I'm willing to believe that, but if it's correct, why all the stereotyping about rednecks, hillbillies, people from the Bronx, etc? I've seen episodes of "Survivor" where cast members have to be subtitled because the accent is so dense, even though English is their first language. (My shameful secret. I watch some reality tv).
When I see shows that have what I think are called Valley girls in them, I can not understand them at all - and yet I can watch, and understand, all the character in, say, "Taggart". I'm not British, by the way.