Received a screening call shortly after submitting a CV and cover letter. After a friendly chat about the role, I was sent a link to a short online multiple choice test. This was pretty straightforward (mostly maths and problem solving type questions). After this, I had another phone call where I was asked some competency type interview questions but this was quite informal. I was then invited to an assessment day. The assessment day began with a talk about the company followed by some Python basics. We were then given a programming test which was to program a basic calculator in Python. In the afternoon there were team exercises where they are assessing your teamwork and presenting skills. You also do a one on one interview with someone where they go over your Python test with you and ask some other general questions about your CV and interest in technology.