Thanks for getting the case history done and the photos up. So going back to your previous email it looks like Robbie needs to lose about 50lbs. which would mean he should be eating a total of 7kg a day of hay and concentrate. That means right now he's getting a half pound over that amount with the addition of the speedibeet to the hay. It may not seem like much but that small difference plus whatever grass he's getting in the pasture can make a difference. I'm not sure there's any benefit to the Advanced Concentrate for him or if that could be a trigger as well - there's nothing in it that should be but again, if he's very sensitive to diet changes it could be an issue.
His current x-rays do look much better than the old ones but I'll leave more specific commenting on his trim to our foot experts.
As far as the paddock - is he still going out where there's any grass at all? If he is you may want to consider a muzzle for him as he appears to be very sensitive to diet changes.
Did you get his bloodwork results back? If you have can you please add them to the case history and let us know what they are?