This wasn't a graduate position so it was your standard three person interview board rather than a group interview. One interviewer was HR, one senior tech guy and the third seemed to be there to make up numbers. The whole process took over an hour and was a pretty intense interview, containing the standard HR questions but then the two tech guys took over and grilled me on my engineering knowledge specific to the role.
This was extremely good interview experience due to the difficulty of the content and intense nature of questioning mainly from the senior tech guy. I found it slightly frustrating as the questions were worded pretty poorly in certain cases and could be interpreted in several ways. I would start answering and then have to be corrected - pretty infuriating to be honest.
For example the question: "How would you go about designing a piece of test equipment for a missile" could be answered a multitude of ways. I started by talking about deciding what we required from the missile to form a basis for testing however they stopped me short and actually wanted me to draw a missile on the whiteboard and state how each sub system would be tested. This is a typical example of how the interview went - me misconstruing their ambiquous questions and having to be led back on track.