I've got an Avon 8 tender. I've dug out my bracket to take a closer look. I've seen stainless steel brackets versions too, so possibly a better finished regards the support area mentioned. The hypalon fabric is more than up to the task, but take your point if your tender is immaculate.
You could add a hypalon wear patch where it makes contact, change the bracket for a revised version - a little extreme considering you've been rowing it for 33 years, or a little Heath Robinson I know, use pipe insulation foam on that area with some gorilla tape for the time being.