I spent most of my interview with Körner wondering if the chair I was sitting on was going to fall apart so I'm afraid I can't be a great help in that respect. Most of the questions he asked were GCSE level knowledge but much harder, so make sure you're comfortable with those sorts of questions. To be honest, my interview with him went really badly and I still got in, so I wouldn't worry too much about it: they seem to place more emphasis on STEP than interviews (be prepared for a 1/1 offer!).
Dr. Tokeida is new this year so I wasn't interviewed by him, but one thing he does seem obsessed in supervisions with is the drawing of pictures to help solve problems. Do this and you should be fine. He's very friendly and may give you tea and cookies!
Hope this helps. Prof. Körner's office is on my staircase so I may bump into you on the 1st.