Had a phone interview with head of media operations in the USA, then met him again in a face-to-face interview in London, along with 3 other campaign managers. These were all 1:1. Then I had two more consecutive phone interviews with US campaign managers. I then came into the London office again for two more interviews with the sales team (there were 2 interviewers at a time in each of these). Final stage, I was flown out to Austin to meet with two of the founders and two account managers (one of whom I had already spoken to). The recruiter then confirmed that I had been successful and sent the contract.