I've heard of Seth's book, never read it. In turn, I'll ask if you have heard of Martyn Skinner: The Return of Arthur, etc.?
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apilgriminnarnia.com]
As you can see from the article I've linked above, I quite liked that.
Skinner also wrote a mock-heroic tiny-fairies poem, Sir Elfadore and Mabyna, kind of a curiosity:
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apilgriminnarnia.com]