The interview day was a group assessment day split up into several sections. It lasted from about 9am to 4pm. It was extremely well organised and an excellent test of candidates' abilities.
1) Group ice breakers such as "tell the group three things about yourself, one of which must not be true".
2) Team work exercise to come up with a social media strategy.
3) Written test on social media, stats etc.
4) One on one interview, about ten minutes, just to find out a little more about your personality.