I agree with the few bad recessions. I guess it's up to the bowl on which the seat is to be fitted. We have because of an old apartment building a probably very ancient dish which is why the Löchter are too close together and the lid is fixed to get so impossible! I'll look for now at the hardware store a seat with other mechanics to fix.
PS: I've just compared the image above with the supplied pieces. There are definitely other installed hinges as in the photo, so I ordered the WCShop24 NO single toilet seat more!