My first complaint about this pair (see Kelly Sullivan and Avond on page 30) is that this horse’s head is far too deep and behind the vertical. My guess is that, in this moment in the stadium, the horse is hot, encouraging the rider’s tight contact and forward upper body. I suggest doing transitions. Get him to react to the bit and then give; make him carry himself and pay attention rather than holding him together. Even if he isn’t hot, do the same thing. He looks like he’s happily going along but not focusing on you. By doing stuff, like transitions, you’ll make him focus on you.
The rider has a very straight line from bit to elbow (as it should be), but the horse’s nose is so low that the elbow is quite straight. She has a good position, but she looks like a hunter rider both because of her short stirrups and because her upper body is slightly in front of the vertical. If you try to draw a straight vertical line through her shoulder, hip and heel, the shoulder is too far in front. She has good leg position, but it is met by a weak seat. I recommend she ride without stirrups, too. The knee specifically is not as important, but let that whole leg be a weight to drag that seat down. It is hard to tell because of her collar, but I suspect that she needs to bring her chin in a bit more. Her upper body is a bit forward, but the head affects the balance of the upper body, so maybe bringing the chin in and the head back will encourage her upper body to be more on the vertical.