Lovely bloke. Very entertaining. He used to run GODS (Getting older dressage society) clinics at our yard and then we'd go out for dinner afterwards. He would keep the whole table enthralled with his anecdotes.
His teaching is very sympathetic and I believe modelled on classical principles. He uses a lot of 'props' like cones and poles placed in particular shapes. His clinics are really intensive - it will be literally "shoulder in down the centre line, now turn left and canter, now trot and circle in the middle, then turn right and leg yield, now canter, now trot etc etc" - but it is amazing to see the difference he can make in just half an hour or so.
You will have to concentrate really hard - 'specially as he is not a 'yeller' - quite softly spoken when instructing but will treat everyone from a grand prix rider down to wallies like me with the utmost respect