The process starts with a coding challenge. If you succeed, you get to the next step, which is an assessment centre typical from graduate employers. I would like to point out that the HR people were not very trusting during the process ("we have no proof that you did it yourself", thank you very much), then you will have to prepare a case study with front-end and back-end demo of a website (without any further proof that you did it yourself, but you get the point).
At that stage you discover that the graduate role is NOT a graduate scheme with a certain time frame, but only the beginning of an Associate pathway where you would choose to specialize as an analyst (user stories, user cases... ) or a developer, when they invite you to the associate assessment centre. Note that at that stage they would also not refund your travel expenses for the interview like other graduate employers do.
The assessment centre though is quite similar to others, maybe a bit shorter, just a few hours. It starts with a group exercise where each person gets a possible solution to a problem, and speaks about it with the others. The interviewers then ask questions, some of them voluntarily counter-intuitive, called curveballs. You then have to present the case study that you prepared, and finally a face-to-face interview about the company and the culture. Notable questions are what project are you most proud of, what are your hobbies, and what would be your chosen nickname. You can then ask your own questions.