https://community.ebay.co.uk/t5/Postage/How-to-change-parcel-size-after-sale/m-p/7916018#M64011 <P>In terms of the Post Office - it's nothing to do with them. Ebay and Royal Mail have an arrangement and the Post Office just needs to accept the packet as quoted.</P><P>&nbsp;</P><P>My understanding is-</P><P>If ebay suggested the weight/size band, then in theory you wouldn't later have to pay any extra.</P><P>If you overrode what ebay suggested for weight/size or typed in a weight or size which was incorrect, you could be charged extra by ebay, later - not at the post office. Or possibly they might raise some kind of query with you once received at the GSP hub.</P><P>Sellers are supposed to check the&nbsp;weight/size band suggested by ebay and change it if necessary. As the difference in price between a large letter and packet is more for international than UK; and some payment may need to be made between RM and the foreign delivery company, then IMO there is more of a case for having the correct size/weight band selected. But unless a seller is doing it deliberately or inadvertently on selling a large number of packets abroad, I doubt ebay would take any action, other than giving a warning and charging the extra plus £1; if that.</P><P>I'm not aware of any situation that the buyer would pay extra.&nbsp;</P><P>&nbsp;</P><P>The general wrong weight/size bit is explained here, but in terms of national delivery, not SD to GSP and then abroad. I've not seen any pages explaining anything extra about SD/GSP/size and weight but I've not specifically looked. <A href="https://www.ebay.co.uk/help/selling/posting-items/setting-postage-options/simple-delivery?id=5575#section11" target="_blank">https://www.ebay.co.uk/help/selling/posting-items/setting-postage-options/simple-delivery?id=5575#section11</A></P> Fri, 22 Aug 2025 10:04:44 GMT str11p 2025-08-22T10:04:44Z