Went to London office for in person interview. Immediately given a 1 hour Power BI exercise to do which I hadn't been told about beforehand. Then spent 1.5 hours on generic interview questions and Q&A. Received no feedback for 2 weeks and was then told I didn't get the job. Asked for feedback and received one line of generic feedback not specific to me. Still don't know why I didn't get job or how I could improve for next time

Interviewer was calm and relaxed and focused on getting to know you as a person whilst also testing your approach to problem solving If you're part of the open day this might be explaining your assessment as well.