Excellent puzzle from Vismut, to whom my thanks. The “Easter Eggs” provided by the non-redundant elements of the down clues were a remarkable jeu d’esprit, so I won’t quibble about 18 - but I get the point.
However, I am being a bear of very little brain anent the final clause of the preamble. I know what the object is but I can’t see the “central character” to turn. There is an obvious candidate in the silvered line but it’s just off-centre. Any help towards enlightenment would be appreciated.