Based on the description in Fairbairn, we may have a winner. Too bad the link provided doesn't show the plate referenced. But the description of a wolf's head couped, with that motto sure looks like a match.

Wish I could use Mr. Peabody's wayback machine to talk with g2-granddad, and ask him which symbol he most aligned himself with. But I bet you that he'd just point to the sign for the local pub, and wink.