I followed several professional training courses with Didier Lavergne (who authored the book « Etre cheval »). His courses were very formative and instructive.
I am currently following a training course with Andy Booth.
Two men, two different cultures, cursus, approaches and technics… I would qualify their respective approaches as parallel and complementary. They are both great horsemen, pedaguoges and sensitive.
They both give you food for thoughts and demand to challenge yourself everyday to become a better horse person.