The RGT exams give you credited qualification in guitar. They are by far the most practical around, Like the Rockschool exams, they deal with the up to date themes and styles, but they do not force you to play exactly the same riffs, chords and lead breaks as a ten thousand other students like you. They are the only exam that completely train the musician to think on their feet. sure we copy stuff but there is nothing verbatim, The work undertaken is a direct reflection of your own style and abilities.  There are obviously specific scales and chords to learn. And also there is of course some general theory, but in the main, student find this exam far less stifled than others.