A.D.I. stands for Approved Driving Instructor.

A qualified instructor has sat and passed all parts of the course needed to become a fully qualified instructor. A trainee has passed two parts of the course and is training for the third. A fully qualified A.D.I. will display a Green badge in the car, where a trainee will display a Pink one.

No you can learn to drive for as long as you like before you take the exam. However you will not be able to take your driving test until you have passed both the theory and the hazard perception exam.

No if you fail either parts in one exam then you will have to take the whole exam again. You will only get a pass certificate when both parts of the exam have been passed at the same time.

Yes the instructor can sit in the car whilst the pupil is on a driving test, but the PUPIL must ask the examiners permission.