My law interview at Oxford was really enjoyable. It was 2 x 20 minute interviews, with a panel of 2 interviewers each. The best advice I received was from a previous member of the Law Faculty. I was told there was no point combing through my personal statement, and that there was very limited preparation I could do. Instead, he told me to relax, enjoy my time in the city and keep myself healthy. This was very valuable advice, as I found there was nothing I could have done to prepare for the interview – surprisingly, there was no legal knowledge required at all. The interview relied solely on how to process and interpret the law, and didn't need to be overcomplicated. It used basic concepts like morals and staying neutral. Thinking about the different applications/subtlety of the language they give you seemed important, and they extensively questioned the laws you formulated and how you defended your perspective.
The tutors were so friendly and I didn’t feel intimidated, as they made it clear that we weren't assessed on confidence, and it really helps to know when to defend your position and when to learn from their prompts.
So my advice would be not to spend hours scouring books, and to keep up to date with broader legal issues just to give you a little more awareness. Whilst the brief concepts of law are useful, do not waste time learning terminology, and just use it as an opportunity to explore the law and jurisprudence!