While you've got the mill down Stew, why not see if you can use your vice and a few spacers in strategic positions to bring it back to square. Once in position, each time you walk by the vice, give the handle a little tweak.
I think brass was maybe the wrong choice of material for that load bearing part, that calls out to be made of ferrous. Then distress it to make it look as though it was original.
I have some nice plate that it could be made out of, and if you haven't got your mill working, I would knock it up for you as well. It isn't a big job at all.
John