I applied via their website, and got an email within a few days arranging a phone interview, which was about 45 minutes long. The interviewer checked I knew what the company did and that I was actually interested in the role, asked some technical questions about my final year project, including for more detail and understanding of the concepts I'd mentioned. There were also some brain teaser type questions.
I was then invited to a face-to-face interview at their office in Cambridge. I had a brief chat with HR about benefits etc, then a tour and lunch with some people working in the team I would be joining if offered. Then there were 5 different people asking a range of questions to assess understanding - Analogue electronics, circuit design, software, mechanical, more brain teasers.
Pretty much everyone was very friendly, the process was smooth and they gave feedback in the rejection email.