Initial chat with HR person for fit (usual questions you could expect) 30m
Follow up with line manager (1hr - go over prior work experience, fit, personality questions, some technical stuff)
4 separate meetings - 2 co-workers, some suit in London and direct manager. 1hr each. Co-worker interviews are the same you get almost everywhere else (why us, tell me about yourself, tell me about a time....). The suit interview was more of the same and the final one was a case study.
Final "coffee chat" with some director. 30m+ Don't get fooled, this isn't a relaxed get to know you. Prepare to get grilled (role-play, deep dive even more than you already have the past 5 meetings, etc.)
It's all a bit overkill as you'll get asked the same questions over and over and over. Maybe that's the strategy but it's exhausting in a "omg, not again," kind of way. They want to see you "excited" about the role. So, if you really want it, be a cheerleader and yay hooray in your interviews or your motivations will be questioned over and over.