Where can I sell a Self-Adhesive label made for GUINNESS (by Avery). It's the only one-of 5- left in the world

Avery Dennison Roll Materials of U.K. (Graphics Division), made 5 self-adhesive test labels (22 3/4 long X 9in high) for LOCALINK (of Ireland- in early 90's) to advertise 'GUINNESS' beer on their Irish bus windows. Guinness rejected the labels and told LocaLink to distroy all 5. Four got distroyed and somehow the 5th was saved. I got hold of it from a trader in a Dublin market. I have spent several months tracking down and verifying this labels maker, origin and authintisity. More info about words and size of words available to serious inquires only. QUESTION: Is there a market for this 'One-of-a-Kind' item and who can I contact to either sell it out right or auction it off.? I will only entertain responses from verifiable dealers or serious buyers.