Now before everyone says push him into the contact and drive his impulsion. It's not working. He has impulsion in excess! I use demi-arrets to some help. I've decided to ride him long and low with light contact, which he'll do, for the time being before my next lesson (also first lesson of the season).
He does have a stiff right neck (has for a year since I got him) and find he ducks behind the vertical 'mostly' in bends that ask him to stretch and round his muscles. So I do carrot stretches, give him a message before and after the ride and always cold rub water/linament after the ride.
Any advice or suggestions?