Really simple. They need you after all. Turn up with all the paper work they have requested from you, they will make the copies whilst you meet the consultant in charge of the area of London in which you wish to work in. It was a general get to know one another chat, finding out who you are as an individual and as a teacher. Your preferences and what you want from the company; your teaching experiences and your long term plans as a teacher or otherwise; and area of expertise. That's all, then they just get to work in finding your a job that suits your needs based on your interview and experiences that you have highlighted.