I had two interviews, both in the morning of the day I arrived. They each lasted 25 mins. On the day I turned up at the porters lodge and was led to a waiting room by student helpers. I then went up to the interview room and was led into the room by the interviewers. After the 1st was over, I went to have tea with my Dad and then went to the second interview in a different bulding.

First interview: There were 2 interviewrs (a PHD student and senior academic) and they started by asking me how the journey was etc (basically to make me feel more comfortable before the actual science bit - they also were clear that they didn't want to shake hands so as to keep the intervew informal and to avoid alienating people who havent been coached for interviews). I was asked about a project I'd mentioned in my personal statement (what I was doing, preliminary results). They then asked me to interpret some climate data from a graph and finally gave me a glass box of insects and asked me about evolutionary adaptations for each of them. I thought the interview had gone badly because I didnt feel especially pushed (because I'd heard that if you think its gone badly, it went well becasue they pushed you and vice versa).

Second interview was with two senior academics (both very friendly). They asked me about an online course I said I did in my Personal Statement (mainly to check that I had actually done it I think). They then asked me about a book I'd read and linked it to the online course. We also discussed bacterial and viral infections.

Massive Open Online Course (MOOC) in Virology using Coursera. These are free online lecture courses and are really interesting + great stuff to put on personal statements. I also had a mock interview at my school (I just asked a teacher, not a specific Oxbridge tutor person). Flicking through stuff I'd mentioned on my personal statement was also helpful.

You've probably heard it before, but the interviews are meant to be a conversation, so talk through your answers, don't come to a conclusion without reasoning it out first and feel free to ask interviewers questions if you're unsure about something. Also don't bother relearning school science unless its stuff you really should know/ mentioned on your SAQ, you'd get much more credit for thinking about things and working it out than having a superficial knowledge of stuff.