The original spacer broke within a few months which made the seat very loose and ruined my time on the throne.
So I decided to design and print a new one in TPU as it's flexible and somewhat slip-resistant. Works great for ~8 months so far!
The seat is made by Scanseat, but not branded (aka. noname), so this may work for many different seats under different names. And I know the same hinge is used by many of Scanseats models.
I bought the seat in Jem & Fix (danish hardware store).
The author marked this model as their own original creation.