Very informal. You will be asked to meeting with at least 2 people (3 maximum) on different occasion. You will likely first meet with the MD who will tell you about the company in general, and gauage your "fit" with the company. Even though the talk seems to be very informat, he has very keen eye, and likely to see whehter you will fit with the organization. If you pass, you will meet with your "next boss" who likely to be Research Director, and he/ she will interview you whehter you suit the position in his/ her team. You might meet with your "future colleague". and that should be all the process