Its no problem mate let them have a hands on with it they will have a health officer or know of one in your area .
Thats the problem with looking a photo's mate I'm not an expert and never claim to be one however its not koi pox .
It may be I've said be Papillomas which in some cases need surgical removal, an immune response or worst case senario Myxolobus (nodular disease) it'll be interesting to know which though and just how far off or near the mark we are on this answer wise.
If I were are gambling man I'd plumb for Immune response
Dave