Fairly straight forward - asked general motivations, why you want to work here, why you looking for a new job, experience, qualifications and where you want to be in the 5 years - job expectations, the wider scope of the business and the structure of the team and also what day to day may look like

Had an initial phone conversation with a member of the recruitment team where we discussed my CV, experience, motivations for applying, etc. Then was invited for a 1st round interview at Mercers London office. This consisted of an interview with the director of the London research team who was accompanied by an analyst. Questions were mainly behavioral/fit. I was then given an excel task to complete and got to question an analyst more informally about the firm/team/role. After a few days, I was invited back for a second-round interview with more senior directors. These were more technical and focused on my knowledge of investment research/various asset-class specific questions. Got a call back within 48hrs offering me the job.