Good luck for Oxford; to be honest with you, though, I have a friend at Oxford doing philosophy, and I know someone from Bristol who knows someone from Oxford doing physics, and in both cases, the teaching and the actual stuff learnt is much better at Bristol than Oxford (on an objective basis). To give you an idea, the people at Oxford did not start special relativity just yet; we're ahead of them in every single field, and on equal knowledge when the stuff covered is the same. Plus, we have 5 hours of
pure labs; they have 5 hours to do the maths and do the experiment, which is overall 4 hours for the maths and 2 hours for the actual experiment. Good luck to them when it comes to making a hologram, or analyzing the Maxwell anomaly in thermodynamics.
The same goes in philosophy; the head of department around here is an absolute world-class teacher when it comes to epistemology. But hey, it might just be my opinion. Regardless, I am very happy of having been rejected for being too "marginal", and I hope never to apply again to Oxbridge

Maths and philosophy? I know someone who will absolutely love what she'll be studying

you'll see, the great many theories of knowledge are an absolute marvel. In the first year of every university, the stuff covered ranges from pure rationalism (what mathematicians love) to indirect realism (what us physicists love), going past scepticism (theologians apparently love it), coherentism, and other doctrines. After that, though, it's up to every uni to make their booklist; I had to read Descartes' meditations and Hume's enquiry on human understanding, which are two
outstanding books. On the maths side, however, if you're good at maths, the first year will be a total bore until you actually get to the theory of fields (vectorial fields, scalar fields, jacobian derivatives and all that kind of junk. Unfortunately, it'll stay abstract; if you want a concrete application of the stuff, either go to a library and ask for Maxwell's equations, or ask me)

This term, it's Rousseau's contract, Hobbes' Leviathan, and Kant's Perpetual Peace Project <3333