Tom Hobbs is your man, I had my 51 plate 75 done by him, I don't think you will find better to be honest, and to echo what Brian has said, unless you are very lucky, once you can see rust like yours it's too late, they rot from the inside out,
https://www.tjhobbs.com/photos.html#
If you click on the photos section the photo on the top row fourth from the left is my 75, if you want more before, during and after pics message me.