You NEVER translate given names, regardless what language. Cities, descriptions, okay, but not people. Or is you country translating names like Tailor, Fisher, Gates or Banderas in your local language? I don't think so. It's called GIVEN name for a reason, it's not a title or job description anymore.
Of course, if you have read it first in german, Beutelin is his name for you, regardless what other languages say.
Translation in children's books are done because they couldn't pronounce it, or it would confuse them while learning their native tongue. LotR is hardly a children's book though.
But okay, if you say those names are already translations from some fantasy language I give it a pass. But only because the sun is shining today!