Yeah, no idea what you're talking about. I'll acknowledge that I'm white, male and come from a middle class background, so yeah, pretty privileged. But when I look at who gets "stick" for their background, it's pretty universally people who come from money. Now, that's not to say that there isn't jealousy relating to upbringing; I am the product of a state school, so I am jealous of grammar/scholarship kids, and generally dismissive of private/public school kids. And schooling is significant; every September the Oxbridge recruiters begin the arduous task of trying to get more state school applicants, and that disparity does manifest itself later on in life.
However, it is never explicit. Someone saying "how very working class of you" is not something that would happen. Hell, I'd consider that person uncultured for saying that. If you really want to talk about British culture's reputation, then the first thing you should talk about is not acknowledging things, responding in a passive (aggressive) manner, maybe looking down your nose, but never ever confronting anyone.
Also, I really wonder how much British culture matters in the tech scene. I'm in London, so that probably changes my experiences, but at my start up, we have 4 Italian employees, 1 Swiss guy, and me, the sole "British" member (though half my family is Polish, so go figure). The tech scene in London is incredibly diverse, and at least in my experience, British culture is pretty far from universally prevalent.