Hi Tarn
The original, German medal, is the rarest and most valuable. These do not come in boxes, or with leaflets.
Briefly, Karl Goetz struck the original medals to commemorate a famous German victory, but when the German government saw the negative worldwide reaction to the sinking, they ordered the medals be destroyed.
The story goes that one or more of the medals made their way to England, and seeing an opportunity for anti-German propaganda, Lord Sainsbury had over 300,000 copies made. The copies were sold in little boxes, with an explanatory leaflet, encouraging people to pass on the leaflet to spread the word about how inhuman the germans were in striking a medal to celebrate the slaughter of so many innocent lives. Proceeds from the sale of these copies went to St. Dunstan's Blinded Soldiers and Sailors Hostel.
Most people will tell you that genuine, original German medals are rare, and are mostly in museums or private collections. They would command high prices if offered for sale. I very much doubt if original medals come up for sale on eBay or anywhere else, despite they being advertised. I have two of the English copies, complete with boxes and leaflets, and I know a number of people who have similar copies, but to my knowledge I have never seen an original German one.
The English copies are made of iron. I do not know what the original German medals were made from. There were also French and Swedish commemorative medals struck, but these were made in small numbers and are extremely rare as far as I can tell.
To conclude, in my opinion genuine German medals are so rare, the chances of aquiring one are slim. Your best bet is one of the English copies. Some medals state the date of the sinking as being May 5 or Mai 5, others May 7 or Mai 7. English or German. I recall finding a detailed account of Karl Goetz on some website which will give you further information if you can find it. I would be worth doing a search on his name.
Regards,
Peter.
P.S. I enjoyed the book!!!