Not a definitive answer, but our local council (Portsmouth) commissioned a "Millenium Tower" and failed to secure the image rights, and are now (unless they pay the ransom demanded by the architect) unable to use the tower on postacrds, T shirts and mugs etc. I would check your contract for the original work, but it sounds as if you have a case. Of course, you would have to prove you created the original design and I suspect that the legal costs may outweigh any financial gain.