Again, some hens are prone to this build up and thickening of the cere or hyperkeratosis. While it’s not real common, this can even appear in budgies fed a good diet. On a hen who has this, yes it’s normal for it to pretty much stay that way. I’d just leave it alone unless it’s blocking the nostrils. It can be softened with a bit of olive or coconut oil and gently hand chippped away, but I wouldn’t cause undue stress for the bird unless absolutely necessary.
As far as finding a good new avian vet, unfortunately there aren’t a ton around in any country, and really knowledgeable ones even harder to find. The majority of avian vets are also regular small animal vets. Keep searching, and call and ask what their experience with birds is. Ideally, you want to find a vet who’s clientele consists of seeing enough birds on a regular basis. Good luck