He has really come so far, as have you, and its brilliant that you acknowledge that!
The one thing i can tell you is in every single picture, bar the third one which is bang on, he is btv. His poll is not the highest point, and if he is ridden btv for an extended period of time, he could possibly become broken the poll (when they get a pointy lump just behind the poll, where the vertebrae are damaged) You may also notice a dip in front of the withers, where the muscle has deteriorted. However this can be fixed, and in your case it is not extreme. I recommend pushing him on a little more, lenthening your reins a frction and letting him take his nose out in front of him. Ifv is much better than btv.