If eBay not willing to deal with this sellers it will be a good idea to report them to Agriculture department. It is known that AD watching eBay auctions anyway, so all we need is to supply them with list of varieties that were imported from oversees without paperwork. So this scammers will not be able to sell most desirable and expensive varieties on eBay-in this case d’Osso and Ponte Tresa.
I will contact AD with eBay ID of sellers and list of varieties they are selling.
It will stop the scam definitely. And if it will affect legal sellers, they will be able to present all Certificates / or whatever you need to present to verify that it was imported legally/ to AD agents.