During my last Standards Check, in February 2015, I achieved a score of 47/51, which puts me in the top 29% of UK Approved Driving Instructors.
Hardly anybody, apart from driving instructors themselves, is aware that instructors are graded. There are only 2 grades - A and B - the next grade is Fail. The problem with having 2 grades is how do you know whether your Grade B instructor is closer to a Grade A, or closer to a Fail grade?
Unless you ask your instructor what their score was you have no way of knowing. If you have any doubts, ask to see their Standards Check marking sheet.
The Instructor will be awarded a grade - A, B or Fail. The gradings look like this:
Grade A - Score 43 to 51/51 “A high standard of competence”
Grade B - Score 31 to 42/51 “A sufficient level of competence”
Fail - Score 0 to 30/51 “An insufficient level of instruction”
Here is my Standards Check marking sheet: