Thanks for all the responses. Chimney's assessment that there isn't a wrong choice is reassuring, especially as she's a senior academic, as are the comments by NiceCardigan and Copperas about their DCs' experiences of pastoral care at UEA, Goldmandra about how nurturing she found Exeter, and all the comments from former students and parents of DCs at Exeter and UEA who all seem to have positive things to say about their institutions.
I'm new to MN and lived in Canada for years, where pretty much everyone sends their kids to the local school, so I find it interesting that the discourse on rahs/public/independent school kids is so heated. Even if they make up 33 per cent of the student body, which I think they do at Exeter, that would still make them a minority. Could they really set the tone of the university? And surely not all posh/public school types are arrogant, entitled twits who lack a social conscience (anyone else old enough to remember AnthonyWedgewood Tony Benn?).
Thanks for the advice from thecalicocat, senua, and GentlyBenevolent about looking at cheaper accommodation for a greater socio-economic mix. That makes sense. There's not a huge price differential at UEA, but at Exeter there is quite a spread.
One thought on Coventry and Essex because I've just read an article about Yanis Varoufakis. Getting a 2:2 degree from Essex hasn't stopped him from becoming a Fellow at Cambridge, teaching at top universities around the world and becoming Finance Minister of Greece (not a job I'd envy, mind you). There are so many elements that go into success. I suspect self-confidence, charisma and determination are probably more important than the undergraduate institution. And none of DD's choices are big enough international brands to mean much for her future prospects.
That said, the pernicious rankings are hard to ignore, even when you know they are BS not measuring anything you care about, and even when you know your DC is more likely to go to the moon than end up in the City. Certainly, it's something DC's classmates all talk about, and I think it may be the chief reason she is hesitating to firm her unconditional. She chose her courses carefully, so she really would be very happy doing either. If she decides on UEA, I will share Tviokh's comments with her.
ragged you asked about why IR, what it means for History and how it could link to Medicine. I think it's because DD has lived in a handful of countries, has friends who come from just about everywhere and is fascinated both by the past and how it links to what is happening in the world today. Looking at what's going on in Crimea, the Middle East, North Africa and the roots of many conflicts... it seems like a pretty good fit. I think that the analytical skills and ability to measure the value of source material that she'll get with a History (or IR/History) degree will stand her in good stead in many fields. Medicine? She also loves biology and very nearly applied for that instead. We have doctor friends whose first degrees were in literature. 18 is young to be making decisions about who you are and what you'll do for the rest of your life, and there aren't a lot of jobs for historians so she's likely to need to find something else.
Copperas that's brilliant information about the Disabled Student Allowance. I'll see what I can find out about it, though she won't meet the three year residency allowance we have lived in the EU for eight years, so maybe that will count. DD has had an amazing sixth form tutor this year who has helped her navigate some very choppy waters, so I know how valuable having a mentor would be, especially in the first year, especially when it hits her that she's a plane-ride away from home. It's also encouraging to know that you work in a history-related field (and that there is work in history-related fields!) and that you think both courses are good. DD has actually seen both campuses we visited last summer but there weren't students around, and she wasn't able to get to the offer holders' days when she would have gotten a much better feel for the universities and departments. DD does love bunnies. Maybe that should be the deciding factor.
For the choice? Since all anecdotal (and other) evidence seems to point to both options being good, once she has looked through the courses, university facilities, activities etc again, if she is still on the fence I think I will push encourage her to go for the unconditional offer and move on. As Tviokh said, it's a blessing.
Apologies for this ridiculously long post and thanks for all the input. It really is helpful.