Yes the seller knows. I recognised his photography style when that image was posted, so I had a delve on Ebay to find out where he disappeared to.
During 2004-2005 he bought and sold many handmade vintage swirls on Ebay including some amazing ones under the name chezbargains and received many very happy feedbacks from collectors. Changed name to vintagemarles and following a neg fb changed name to vauxtigra and merged the account with his non marble id ive856 which only shows vauxtigra in id history, so hiding the marble id's forever, unless you search find member vauxtigra then they are there. The marble fb still shows on the ive856 id but no one would scroll back that far to see it.
One quick way of getting a good overview of a seller is to put the id into toolhaus fb checker for negs or neuts, the ive856 id brings up 7, 2 relating to marble transactions. That alone would ring alarm bells for me.
He no longer lists on Ebay UK, so probably found a better market elsewhere. And I totally agree it would be boring if every disputable marble was brought up here as many sellers are unknowlegable or hopeful, but this one knows what he is selling.