I went through two sessions. The first session was with the HR. It was a good session, but you are expected to do your own homework about StashAway. She shared me a couple of other inner cultures within StashAway and you may also discuss other topics such as investment and general work satisfaction.
The second session was with the CTO and one of the tech leads. You will be assigned with a mock engineering problem, and expected to come up with solutions to the problem together with them. There will be assumptions on how things work and it's best to raise them up during the discussion. It was a good session for you to be able to evaluate on how discussion would be like in StashAway itself.
Overall, I enjoyed the interview.