Rory, I have to agree with Addicted on this: the rules state that only the original release (which in this case can be considered the existing cover) should be entered. However, if you share by voting, then there are a lot of users that can or might miss your cover (I was abroad the past 3 weeks for example and barely had access to Internet, to state one example)

If you submit it to Chris in his dedicated thread, the cover will stay available for all interested parties for as long as his site is up.

Just a friendly suggestion ...