Well, if that's the case, they need to update their used clothing pages:http://pages.ebay.co.uk/help/policies/u ... thing.html
Used clothing may be listed on eBay, so long as the clothing has been thoroughly cleaned according to the manufacturer's instructions and is stain free. Used underwear including, but not limited to, boxer shorts, panties, briefs, athletic supporters and cloth nappies is not permitted. Listings that contain inappropriate descriptions will be ended.
And diapers does sounds American, rather than the co.uk site.
ETA: A quick Google shows the text in the OP appears on ebay.com so probably doesn't apply here: http://pages.ebay.com/help/policies/used-clothing.html