Perhaps Laurence Mills may have had access to the Ven's draft MN? Did any of his notes ever make their way into the Mahamakuta edition of his "A Treasury of the Buddha's Discourses from the Majjhima-nikaya"? I lost both volumes when I was moving home.
But I'm puzzled by the Ven's point. If there's a search for this ontology, one might look to √bhū, surely not √bhu as suggested by the Ven. Or was this just a typeset error in footnote 46/1?