Your instructor must be Approved or Licenced ...
Approved Driving Instructors (ADI's) have passed a tough examination in order to demonstrate their skills. They are also checked and graded regularly.
Fully qualified instructors display a green badge in the windscreen.
Grading can be A or B - both are acceptable but A is a higher standard. Some instructors get a C grade, this means that they were unsatisfactory on their last check and are awaiting a re-assessment - these instructors are under review and risk having their tuition licences revoked.
Instructors are issued with a certificate which shows their grade, they should be happy to show this if asked.
Licenced instructors are in the final stages of training and qualification. These instructors have undergone a minimum required 
training programme and but have not yet passed the final qualifying examination.
training programme and but have not yet passed the final qualifying examination.
Licenced instructors display a pink badge in the windscreen.
While Licenced Instructors are expert drivers and have learned the basic teaching skills, they have less than six months experience in the job. Although Licenced Instructors lack experience, they are invariably enthusiastic and have been trained to the latest standards.
Your instructor's photograph will be displayed on the rear of the pink or green badges (just like on passport photos, they might look like convicts!).
Some instructors will have further qualifications such as special advanced driving certificates, teaching diplomas and even industry related degrees. Generally speaking, better qualified and experienced instructors will offer better value (although the might charge a bit more), however, take note of the warning advice below.
Legal Stuff
It is illegal for anyone who is not an Approved or Licenced driving instructor to charge a fee for driving tuition.In addition, the instructor must, by law, display his/her certificate in the windscreen during lessons.
