Something to remember about the definition of "miniseries" is that British television series of any genre are usually much shorter than American ones. It's the default for a sitcom or minor drama to have a series of six episodes; flagship dramas might have ten or twelve episodes per series, but this does not mean that a show with a shorter series is considered a diversion rather than something for more long-term consideration by the viewer.
It's just that production cultures differ from country to country. Writing teams in UK productions often consist of just one or two people as opposed to the large writing teams seen on major US shows, though I'm sure that's subject to variation.
I'm finding this whole discussion fascinating; shamefully, it's not a subject I've considered much, and it's interesting to learn how another culture defines class. For instance, I was surprised to see teachers listed in the working class section; in the UK we'd see them as middle-class like doctors and solicitors, despite their getting less remuneration and respect.
Also, from a UK perspective I wouldn't necessarily rule out a character getting a university education, because you can be from a working class background and still go to university. But I get the feeling that in America class is defined more strongly by money than by family background; that you can be said to become middle class by the act of going to university/getting a well-paid job. Would that be accurate, or are there more grey areas?
TV shows... Eastenders and Coronation Street are indeed good examples; soaps in Britain tend to be less aspirational than in America and how people live is expected to reflect the reality of an equivalent real-life social group (even if, for dramatic purposes, there are rather more murders, affairs etc. than in the average street). I don't watch a lot of ongoing serial TV at the moment and I tend to have heard of things/have a sketchy idea of them rather than know much stuff for certain. It's usually a fair bet that anything set in the north of England will be pretty working class-centric, though.