May I make the most gentle of riding critiques? I see that in the photos his head is behind the vertical a lot, and it looks like he is leaning on the bit. Over time, he may learn this way of going, and if it becomes a habit, will become evasive of the bit by coming behind it. It's a very hard habit to break.
Sometimes, eventers have a ton of teaching and experience on jumping (something I know nothing about) but the dressage area is left til last. They might think that having the hroes's head pulled back in an arch is the correct way. It is something to look into once you have the time. Please forgive me if I overstep my bounds. I know this is not a crit thread, but you seem so excited about your new horse, and he is really a lovely horse with a ton of potential for both jumping AND dressage.