Another update for Michelle as this is by far the easiest way to post comparative photos.
The top photo was taken when he arrived, the middle one last week and the lower one yesterday. This is the foot he is reluctant to engage heel first - you can see whey - and it has become a bit of a vicious circle when lack of engagement = palmar foot pain = weaker frog and digital cushion = inability to land heel first = more deterioration.
We are trying to help him break this cycle by allowing him lots of time on surfaces where he is comfortable but is also getting stimulus to the frog and digital cushion and lots of in-hand work in the school to try and encourage better patterns of movement.
At the moment Columbo is very unhappy with any poking or prodding in this area, which is understandable, but unfortunately getting in there with antibacterial and anti-fungal spray is a necessity at the moment.
For those who are interested, I've uploaded his footage here - his landing is still pretty stubbornly toe first on his RF particularly though it feels as if he is teetering on the verge of something better - he is beginning to land better going downhill, for instance, and in the school.