Well, do more preparation than one day in advance (hopefully you have been!)
A Cambridge interview is a conversation. Relax and view it as a chance to talk with a world-leading academic, and you'll get more out of it than you will if you're super defensive and view everything as a trick question or a trap. They're not trying to catch you out - they're trying to find the right questions to let you show yourself off (this is a hard job, cut them some slack). They'll deliberately challenge what you're saying because they want to see how you respond; while you feel you have argumentative ground to stand on defend your position, but yield once it becomes apparent that you're wrong. They want to admit applicants they can teach, not stubborn serial debaters who think losing an argument is grounds for ritualised suicide.
There's no 'set list' of questions either. As I said, this is a conversation and your tactic should be to steer the interview onto areas you feel you can talk confidently and interestingly about. Let the discussion flow, but you should always be thinking about ways you can maximise the short time you have: how can you synoptically weave in other stuff you've read? How can you make that interesting point you've prepared in advance? How can you show off your reading to the best of your ability? That said, there are some questions which do recur. Basic ones like 'what have you been reading recently?' are obvious and are a gift vis a vis allowing you to shape the discussion. They also often ask quick-fire 'what have you read from x century?' type questions (more on this below). They can also pop you with harder ones: 'what is irony/ambiguity/tragedy/etc?' is a classic. It's also quite an unfair question because regardless of your definition you'll be wrong, so bear that in mind when responding.
For reading/prep, your A-level course is the start point. Your personal statement should stretch beyond that narrow curriculum, but you must have other things to talk about beyond your personal statement and A-level curriculum. You must demonstrate significantly above-average reading which is both broad and deep. You must demonstrate that you're operating on a much higher level than almost every A-level candidate: what are you reading to challenge yourself? Are you already doing university-level content? How are you going supercurricular? If you arrive with nothing but your personal statement to talk about, they will find out within two minutes and you'll almost certainly be rejected. Make a wall chart and split it into two boxes for every century from the 14th to the 21st. One box is for prose, the other is for poetry. You should have at least one text in each box which you are confident in your ability to discuss interestingly by the time you get to interview. This will give you excellent breadth and allow you to make synoptic connections between old/new literature, which is a godsend for steering the discussion and seeming interesting and broad in your reading. Try to avoid hackneyed choices: I'd advise filling this chart with interesting canonical books. Avoid GCSE/A-level texts where possible, avoid really long books (give yourself a break and pick things which are nice and short), and avoid what my friends jokingly and disgustingly arrogantly call the 'I applied to Oxbridge and now I'm at Durham' applicant starter pack, which runs as follows:
- I read Chaucer's Wife of Bath's Prologue/Tale and now I'm confident enough to assert that he was a proto-feminist
- I read Jane Austen, pretty sure she's a proto-feminist
- I read Northanger Abbey, I think it's a parody
- I read the Brontes
- I read Virginia Woolf and she's all I want to talk about for 20 minutes
- I read Twelfth Night, golly isn't there some gender-bending going on there which I don't think anyone before me has ever noticed
- I would now like to talk about romantic poetry (Wordsworth, Coleridge, Byron etc) and nothing else for 20 minutes
No, no, no, no. They get that content
so often, and it'll bore them. Find interesting stuff to talk about, or if you must do the above at least find interesting angles (eg I did talk about romantic poets but I related them to 20th century dystopian literature). Fun tip: look up your interviewers online beforehand and see what they've been writing on recently. See if any of it overlaps with anything you've done/have heard of, and prepare a bit on that. Then derail the interview onto that content; they'll enjoy talking about their own field and it'll be a more stimulating interview (hopefully).
Quick-fire misc tips incoming. 1) Take some time to think of your answer before wading in - ask for a few seconds if you need it. This is way better than panicking and offering a bad/rambly response. 2) Make eye contact with your interviewer and mind your body language. It sounds silly but just relax and be warm and affable. 3) Do lots of mock interviews (good you're already starting), and not necessarily with English specialists. I did a couple with random teachers, on the basis that they'll be less informed and thus will ask natural questions which will cause the discussion to flow more like it will in the real thing, and it'll also alert me to moments where I don't explain myself properly/I paraphrase/make something sound complicated. 4) Get to your interviews in good time, if you successfully get invited to the real thing. I lived far away from Cambridge so I came down the night before and stayed over, and I'm so glad I did: it really reduced the stress and tiredness of travelling and let me meet other candidates the night before which was super relieving and just made it a more fun experience overall. I'd arrive to my actual interview about 10 minutes early (it can be tricky to find the room sometimes so allow time for that) because I - this is terrible and I feel guilty - liked listening at the door to the previous candidate. It chilled me out.
Was any of that useful? Good luck with your mock interview