This is why we just don't go pure show jumping as our local venues seem to be full of kids & older for that matter just yanking, kicking, thumping on backs, a horrible sight to behold, as is most of what comes out of their mouths as well.
Makes my heart bleed looking at the majority of those photos as most are showing signs of facial pain - I absolutely HATE HATE HATE that they can race ride on the roads - that is disgusting & needs to be BANNED.
I would definitely speak to him so you know exactly where you stand going forward with his charges etc.
Sadly speaking from personal experience I am so glad to be barefoot now so as not to have to deal with either loosing shoes or being at the mercy of farriers.
Exactly SEL so many people rave about all these products/ideas but when its done in conjunction with everything else management/diet wise why cant they see its the management/diet that's made the difference not the bloody double cream - big sighhhhhhhhhhhh
Struggling with correct canter leads can be a sign of pelvis issues have you had him checked by your physio?
We had this with our cob & physio has greatly improved it
Also straightness training helps as most just like humans have weaker & stronger side.
If he is barefoot he will have far less concussion from the ground - strange really as we all think shoes = comfort/protection as with humans but actually its the opposite most of the times with horses as its the frog that cushions the landing so if you have big healthy frogs that's ideal.
We find ourselves in a similar situation with our connie who had glandular ulcers but on top of that have my daughter is not the right partner for him.
He has currently been turned away for a year but we are planning to restart him first revisiting all his groundwork, long reining etc to...
We recently found that although the haylage supposedly has a lower sugar content our ponies just did too well on it!
Being a first time user I didnt realize it was rye haylage which was just too yummy & rich. We then switched to meadow haylage which is a lot drier & not as tasty.
We too have a cracking coblet we are eventing, what has worked for us if having an Instructor who also riders her as well so she totally gets the feel of her & can translate that perfectly to my daughter - its been very helpful indeed.
We had a ticking time bomb & turned out to be glandular ulcers.
Alfalfa sent ours over the edge totally.
Stop the feed.
Get a proper work up done.
If nothing found Id always scope for ulcers.
Also have you read up on Sue Dyson facial pain expression - very interesting & useful diagnostic tool...