In 2018 Ebay seller agaplatesuk from Redditch in England was selling these completely fake Alderney, Jersey, Guernsey and Gibraltar plates as genuine used plates. He was previously worldplatesuk and foushekas.
These plates were made by him in his garage/shed from plate blanks, stick on letters/numbers, county blue bands and riveted numbers/letters that he has bought on Ebay and at junk shops/antique auctions/etc.
He must think buyers are stupid not to notice that even though these are different countries, his plates use the same stickers, blanks, holes and numbers/letters. He nearly always has blurred photos (on purpose no doubt) and never shows the backs of the junk plates he sells.
Do not buy from this seller is the only advice I can offer. Several people have tried to get him banned from Ebay but Ebay want his money more than they care about what sort of fake rubbish he sells.