Here's a manual I created about changing material names.
It includes example files in a separate zip.
(I'm not that good at creating manuals but I think most users will understand what it says.)

https://www.mediafire.com/file/mm4isi2up7clhyb/Change_Material_Names.pdf/file
https://www.mediafire.com/file/9sud9x34ko2nr9r/Change_Material_Names_files.zip/file

@Emmanuel
If you think it's good enough you're free to add it to the Sweet Home 3D help files.