While the Centre Coordinator is one appointed teacher for the whole school, the Supervisors are chosen by students according to their preference and needs. When it comes to selecting a Supervisor, some students are quick to select a teacher within the field they have chosen; a chemistry teacher for a chemistry-related project, a psychology teacher for a psychology-related topic, and so on. It makes sense to many.
While this may seem intuitive and obvious, there are actually great benefits to choosing a teacher on the outside of your chosen topic area. Perhaps the greatest of these is that if you want a teacher without the specialist knowledge of your chosen field, the bond between you is strengthened as the two of you, in the words of AQA, “embark on the learning journey together.”
Ultimately, you should choose your Supervisor based on who you think you will work well with, and which teacher has the time and will to devote regular meeting time to you. If you choose a teacher, for example, who has many other responsibilities (a Deputy Head, or Head of Year, for example), you may find it harder to find time to meet.