Good morning timsalt,
I orderd 7 screen protector for apple watch 7 with 45 cm in a package for under 10 Euro. It should be fixed. 
A screen protector with round corners! 
Thank you for your advice to fix scratches. 
I have some too, because the wooden wall of my playground for EMO was to high and scratched on the screen of EMO. 
Here you can see how it looks like.