Have you spoken to Clare about the fact that Dylan isn't neutered? I know a number of neurologists who have recommended that people neuter their male SM dogs (in particular) because they get far more worked up and excited when intact and this of course causes the CSF to circulate faster which is what contributes to the formation of syrinxes and pain. Unless there's a serious reason why he cannot be neutered, I would think it might help with pain for him to have a neuter done. Know three dogs off the top of my head who have had this strongly urged by their neurologist.