As a seller and buyer I find it useful to state the actual shipping costs when offering Worldwide shipping.  When I am selling I always offer worldwide shipping and list the costs. I find it saves a lot of time answering emails if i list the shipping costs for Zone 1 and Zone 2 which can be found easily on the royal mail website.  Also when i am buying from a country other than my own, I always prefer the ones that have the shipping cost listed which saves me time having to ask and wait for a reply which can be awkward if the auction is ending quickly.  The sellers with the costs listed are the ones I save in my favourites, therefore they are the ones who get the repeat business from me.