Revolut interview questions

HR contacted me for the first time 4 months after I had initially applied. They said they liked my CV and invited me for an interview. They explained there would be an initial call, then a take home coding challenge, then 2 more Skype interviews. The first call was basic stats / machine learning questions, the coding interview was to build a robust model and nice visualisation using a kaggle house price dataset, the final interviews were more technical and about my experience and why I wanted to join. I learned a lot about the fintech startup industry and the coding challenge was really fun. My problem with the whole process is that my code from the challenge was never discussed at any stage (so I guess they just skimmed over it to see if I could pass to the next stage even though I spent a lot of time and effort on it). And secondly, in our very first call, HR asked me what my salary expectation is and when I told them they said that should be ok. When I got the offer though, the salary was £20k less then what I originally asked for. They could have saved us both a lot of time if they just said no at the beginning. Offer was for £45k per year with stock options.