my vet is a qualified dentist and is good..Richard frost, hawkedon vet surgery....not sure how far north he would go as his place is in Suffolk about 25min drive to the Essex border just to give you an idea.
I'm not too sure where you are in Norfolk, but if you're within travelling distance of Fakenham, I'd strongly recommend Toby Kemble of Wensum Valley Vets. Unlike those without suitable authority, he can and generally does give a mild sedative and with a dopey horse, he has the time to make a thorough and professional job of it.