My interviewer was not in the office and spoke to a few other employees that were not expecting to talk to me. I was told that they would be in touch to arrange a 'second' interview. I didn't hear back for a long time so emailed HR for an update, they said they would be back in touch in the next week. When this didn't happened I emailed again and got the same answer. After chasing them for several months, where they would insist they would get back to me soon, they eventually stopped replying.
One of the employees mentioned that they were surprised I got through to the first interview. They said the hiring manager normally just keeps sending out analytical tests to candidates then tells them they are unsuccessful.
Although the reviews on here are mostly positive, my experience with them was very negative. I got a very strong impression that they gain satisfaction out of wasting other people's time. If you are applying, don't let them walk all over you as there are plenty of FinTech startups in London to apply for.