i think the top pic is the start of bascule, it shows most when the horse is rounded in mid-air over the fence (curved, not hollowing, kind of thing), so if the pic had been taken a split second later, it would show a good bascule.
Personally I would say that although his neck is correct he is not pulling his tummy in and therefore pushing and his back up to be correctly basculing over the jump, but it is at an odd moment.
I think that generally horses tend to bascule a bit more with the biggest fences, like the one the grey is jumping, but it looks like he makes a nice shape to me.
If you think about a curved line from tail to nose (over the back) then you are there By doing this they also engage their stomach muscles and pull those up, giving them the best opp to clear the fence
ah its edwardo! look at him go dont ask me about the bascule thing coz i haven't a clue but i think he looks like he knows what he is doing. A bit like how he knows what he is doing over the 4ft odd gates he pops over he looks fab x