You will probably be interviewed by Dr Tim Kelly, he is a friendly young looking doctor, by that i mean he is not the old professor looking doctor, he wont intimidate you or ask you hard questions probably just tipical logic questions, he will ask you the cliché questions like in all interviews to why you chose york and so on.
His main interest is critical systems, so research and learn about it and impress him that you have an interest in such things. Remember just studying hard is not enough as its a high ranking university and you will be asked if you do extra curriculum activities and your interests in computer science.
good luck.