Spending time wandering around the internet when my wife would have doing something productive (like bringing order to the chaos of my "study") I stumbled on this website:
I was actually looking for a specific habaki reference when I found it. The website appears quite extensive if seemingly trivial, however I saw a reference to the Wolverhampton Museum Collection of tsuba, so I googled wolverhampton tsuba and found lots of related hits. A surprising hit told of a man, Ron Dutton, who was inspired by the tsuba collection to create medals:
I don't remember reading about the Wolverhampton tsuba collection on the Board...
Within the first link is a variety of interesting descriptions about Japanese metalwork, including a ternary plot of the colours of Au-Ag-Cu alloys that I hadn't seen before.