IMHO the most important element of this story is your peace of mind. If you can obtain that, you've won. It is unfortunate and it has made your vehicle more difficult to sell and a bit less safe to drive. So I'm glad you're planning on a fix.
Finally, I'd write a hard-copy letter with some of your photos printed out and attached.
There is no guarantee it'll return satisfaction, but I think the act of expression to the authority will make you feel somewhat better and it will probably go somewhat further, as in some questions getting asked of the fellows on the route.