My son has completed two interviews with senior independent schools for 11+ entry.
One interview was scheduled for 10 minutes, involved him solving four verbal reasoning sequences in three minutes, reading a poem aloud, and briefly discussing a piece of work that he had completed in the last six months that he was particularly proud of. On the latter, boys turned up with pieces of art, school books, and one with a practice exam paper where he had scored 98% Mathematics. Prior to this interview he has sat examinations in verbal reasoning (multiple choice), mathematics (multiple choice) and english, which had included a 20-minute essay.
In the other interview that was scheduled for 30 minutes, he was asked to read aloud a longer passage, orally do a comprehension with the deputy head teacher, give definitions of approximately ten uncommon words, have a mental arithmetic test, go through the reference the school had written for him and then be probed about his career aspirations, interests, last book he had read, favourite subject, competitor schools that he had applied to and why etc. Prior to this interview he had sat examinations in verbal reasoning (multiple choice), mathematics and english which included a 30-minute essay.