I was employed by the NHS for 3 and a half years, as said before they are awesome to work for, lots of holidays, pension etc, also it is great working in a hospital environment.
I have had six interviews with various hospitals (I kid you not), they usually have a panel of 3-4 people interviewing and tend to ask wishy washy questions such as : Why did you apply (obviously) what is your best/worst quality, what would a friend say about you, and they will go through your application form and ask you questions on that.
Take a second to think through your answer before you reply, make good eye contact with all the interviewers, possibly bring along any certificates or portfolio they may want to see, have a good nights sleep the night before, speak confidently clearly and slowly, don't say things like uuuuum...make sure you turn up early and have clean ironed clothes, and wear your lucky underpants.
Hope this helps