The job was posted on their website page and I decided to give it a go. Within a couple of days, I received a phone call inviting me for an interview at the headquarters in Derby.
The interview was conducted by the head of department, 2x senior engineers, and the HR representative. It was quite intense and lasted for 3.5 hours. They were a friendly group and tried to make me feel very relaxed with no silly questions. It did get technical at some points in the first interview, but the real test was the second interview, where actual technical scenarios were presented to me, to see how I would tackle the problem. I don't think that they weren't looking for the ultimate solution, but just the drive and capacity to digest the situation into manageable tasks - easy if you're an engineer at heart.
The work environment looks dynamic, with a large open-plan office, where I saw colleagues easily consulting each other (which is not the case in other companies)