There is interest on ARRSE as well!
http://www.arrse.co.uk/cpgn2/Forums/.../start=30.html
Let's go for it! How about a "broken covenant" as a symbol?
A parchment scroll torn in two?
Those who have PVRd can take a copy of their attestation/commissioning scroll and tear it up at the gates of No 10 or in Parliament Square!