Good company interview. Two panels, 1 hour each.
Both panels of senior leadership/management and both included an HR representative.
10-15 questions each requiring short, succinct but descriptive responses. Interview ended with interviewee allowed to ask questions (depending on time remaining)
Would suggest finding out everything you can about agency before interview, make up a list of anticipated questions and asking contacts to look at your list and let you know if anything is missing.
Practice your answers.