Fabricating a replacement is really easy. You can buy 0.25" partial sheets of acrylic at most sheet supply houses. Leave the protective paper on, and place the old part on the new... convex side down and roll it up and mark your new pattern. Cut it with a fine, sharp blade in a sabre saw and be sure not to force it so much that it starts to melt. File, then sand the cut edge down with successively fine paper. Then peel the protective sheets and flame polish. Any propane torch will work. Now jig up the part and use heat lamps and or a good heat gun to heat the piece and bent it into shape. Do this slowly and heat both sides. Once you have a nominal fit, over bore the mounting holes to allow for expansiion and contraction and mount it.

Bob Kassal