really dont worry about the interview, i got myself abit worked up about it before hand, but once you're there they seem to want to make you feel as relaxed as possible, and it tends to just be general questions, i wasn't asked anything specific really. interviews seemed to be more about the fact you could commmunicate than what you actually said. i had interviews at Manchester, Bath, Nottingham. portmouth asked me to attend an interview, but because i wasn't that keen on going there i rang them up and said i wasn't going and they still offered me a place! so really don't worry about it!!
as for work experience most people i talked to had some, but i didn't talk to everyone!but it is definately better to have it than not.