I applied online on Eccella's vacancy page.
1st stage: Skype technical interview.
This was the most difficult part of the process. The whole interview took about 1,5hours. At the beginning they asked about some technical knowledge about databases, database management, sql queries and algorithms in general. The second part of this stage was to discover the problem solving skills. They explained a problem and asked about the solution. Some of the problems were in the form of riddles. It is worth pointing out that they did not expect a solution right away. They gave hints and they wanted to understand my way of thinking. So don't panic if you do not find the solution but you can prove your ability to work through a problem.
Stage 2: Onsite interview in London. The inteview took place in the cafe at the ground floor of the building that they are located. The interviewers were really friendly and approachable which helps to control the stress of the interview. The discussion was about the CV and the cover letter, the general background, other typical competency based and HR questions. Be yourself and don't stick to prepared questions as the interview adapts to the responses you will give. After the interview the took me for a tour upstairs, in the office.
Stage 3: Final onsit interview and offer. This interview took only about 15 minutes and consisted of a bried background discussion and typical HR questions. Then you discuss the offer.