Submitted CV online, very easy, no cover letter - I wasn't sure how interested I was but since it's only a CV it takes very little effort. Invited to a first interview at their offices. This consisted of 4 short tests - maths, verbal reasoning, and 2 short ones on the company itself and what they do. Maths one is more challenging than you might think, wise up on GCSE stuff at least! Also read the handbook for the last 2. Verbal reasoning is easy. Other things included a short pre-prepared presentation on a topic of your choice to other interviewees + HR, and a brief very informal chat with a current employee, fairly standard questions (why brainlabs etc.) I was invited back for a second interview, which - for the role I applied for (Account Director) - started with an Excel-based exercise with a (super-friendly) employee. They'll talk you through this, and will at the end ask some questions. A bit of familiarity with PPC helps but isn't needed, and very basic Excel use helps - the questions are the more challenging and interesting part! Then finally 2 interviews with 2 more senior people in the company, including the head of HR - 1 fairly standard HR-style questions, the other more different (what makes you happy? etc). I didn't get an offer, but the whole process was pretty enjoyable, and I must commend them on a very classy and slightly amusing rejection email from the CEO, complete with other job suggestions (actually decent ones). Sure, it's the same email for everyone, but it was a nice touch. Disappointment also mitigated by a simultaneous offer from another place I applied! Seems a really great atmosphere they have there. Also felt like they actually look at reviews on here and act, e.g. regarding the rejection email, which was previously criticised. I'd advise not over-preparing on the HR side, I think that was a mistake I made, sounded too rehearsed. They're probably after something a bit "different". By the end I felt it wasn't quite right for me, and as such I commend their judgement being the same!