And the case has highlighted problems with the Feedback facility designed to instil confidence in buyers and sellers.
The buyers have set up an eBay account and posted a £0.01 'information only' listing that appears beside the suspect items in the search lists.
Their move comes after eBay failed to act despite complaints from respected pottery historians about a seller whose listings include items of Sunderland lustre that have been embellished by recent overpaint.
Dick Henrywood, author of several books on 19th century transfer-printed wares, Myrna Schkolne, author and lecturer on 19th century Staffordshire, and Stephen Smith, who runs a reference website devoted to Sunderland lustre plaques, say collectors have paid high premiums for items they believed to be coloured at their time of manufacture.
While eBay seller 1079edmund from South Wales sells genuine pieces of transfer-printed pottery of a type most commonly associated with the potteries of Sunderland and Newcastle, complainants say many are heavily rubbed wares that have been repainted or simple black transfer wares now embellished with coloured enamels.
Stephen Smith, whose website is www.matesoundthepump.com (the name refers to a verse that appears on some particularly desirable Sunderland plaques), believes a distinction should be made here between honest restoration and fakery.
"Restoration is bringing an item back to its original condition. Fakery is the wilful attempt to deceive people into believing an item is something it never was, in order to get a higher price for it."
Definitions aside, 1079edmund typically lists his over-painted items as surviving in excellent condition.
The embellished wares (typically applied over the glaze with household gloss paint) fail to achieve the iridescence of those fired in a kiln. The enamels are often in colours not used by Victorian potters, for example a shade of green and an orange/brown, and are applied with careful brush strokes rather than the broad washes seen in genuine 19th century enamelling.
Mr Smith recommends those who suspect they might have purchased a redecorated piece should try scratching the pink 'lustre' with a fingernail (Victorian lustre under a glaze will not make a mark) or rub a hidden area with white spirit (recently applied paint will probably stain the cloth). He has even taken Nitromors paint stripper to a plaque he owns to reveal a rubbed - but, in his opinion, far more attractive - plaque beneath. This, however, is not to be recommended on all pieces: while underglaze lustre and enamelling won't be damaged by paint stripper, some plaques and jugs have hand-painted script or dates over the glaze.
When Mr Smith checked the buying history for 1079edmund, he found some of the items in their original condition before embellishment. He displayed 'before and after' views of some of these pieces on his website.
EBay have also been presented with this information but have taken no action against a seller who apparently has an exemplary record as the vendor of more than 400 items. His 100 per cent feedback is full of glowing comments from buyers who are clearly unaware the items they purchased may have been embellished. "People who don't know they've been duped leave positive comments," said Mr Smith.
When the seller recently listed four more over-painted items, eBay buyers took matters into their own hands by setting up a new eBay account and posting a £0.01, entitled Fake Sunderland Lustre plaque information only, that appears beside the suspect items in the search lists.
EBay allowed the information listing to run, which gives pointers about identifying recent over-painting on items of lustreware. It has received many voices of support, through the 'ask a question' feature on the listing - and also appears to be having the desired effect. A Sunderland pink lustre wall plaque with a maritime verse c.1840 with notes stating that the "condition is outstanding" failed to make its opening bid of £25, prompting 1079edmund to withdraw two of his over-painted items. Moreover, two previously satisfied buyers have left follow-up comments about over-painting to their originally positive feedback.