Geography, IR and/or Politics
Those are relatively generalist Social Science subjects (although most universities would award them as a BA). TBH, with generalist degrees, as long as your DD goes to a university asking AAB-ABB, then she'll get a very good education. Most UK universities in the top third are all excellent.
The A level grades asked for give you an idea of the combination of challenge of the course (ie the grades are set to give an indication of the level of achievement we expect students to start with) and popularity of the course (A levels can be used as a way to limit intakes).
So then the search for a good selection of 5 universities for the UCAS form comes down to the "feel" of a campus (which you've already articulated), but your DD should also be very sure to do her research on the structure & coverage of specific degree programmes.
You can go beyond the UCAS recruitment web pages for most universities (tbh it's usually easier to do this at the better universities than at the post-92s), and get to the DEpartmental pages which contain information for current students.
Have a look at what staff are specialising in their research: are there people doing researxch, writing books, on things she's interested in?
What is the structure of the course overall? Is there choice? Where & when does the choice come in the degree? Is there the option for a placement or a semester/year abroad?
In geography, is there a lot of maths or science-based stuff in the degree, or is the emphasis on cultural or social geography. Ditto in the Politics/IR degree programmes: sometimes these can be economics/maths based, sometimes more historically oriented.
So it's worth looking at, for example, what are the compulsory core modules for each degree programme she's interested in? Optional modules will change more frequently according to staff interests and availability, but core compulsory modules don't change so much - staff generally rotate in & out of them.
You can do this pretty much all online, before going to umpteen Open Days.