Is there much that can economically, easily, and effectively be done with a loose arbor in a Second Generation Colt 36 Navy? All advice or links welcome.

I don't know of any competent gunsmith in Europe, let alone England, that has any knowledge of such things BTW!

I believe that Colt used Uberti to make the guns that were then shipped to the U.S. to be finished and assembled. I would give Uberti a call and see if they can help.