This is definitely a copyright infringment issue; however, I hesitate to offer advice since U.K. copyright law may be different from U.S. copyright law. The best (and most expensive) approach is to consult a U.K.-based copyright lawyer.
In the U.S.--and I suspect the same holds true across Europe and most other countries in the world--the designer or original author of a work holds the copyright. An original artistic creation is protected under copyright law, and the copyright automatically applies to the original work after it's designed. Meaning, the author isn't required to officially declare it copyrighted or add the (C) to the design.
Copyright exists automatically in an original work of authorship once it's fixed, but the copyright owner can take steps to enhance the protections (i.e., registering the work).
Again--this is U.S. copyright law, but I suspect it's quite similar in the U.K.
