There was about 3 months between initial tests & interview for me. Time scale is fairly up to you as you book your own slot on the system from several available - if you can't make them - wait a while and more will come up in the following months. Interviews are all held on the same day - few candidates just rotated between personnel, tech and computer stuff on my day. Dunno about 2nd interviews but I can't imagine they do as it seems a fairly cut and dried - your either in or not - process.