So should this time something better and to my great surprise I discovered here is that there must not even be so much more expensive!
I was in a small package and a few days after the order my new lock cylinders, packed neatly and securely, and even found a cylinder retaining screw (though in my case unfortunately vieeel too long). At the 5 keys provided
All in all, the exchange completed in no time and now there is also the opportunity to unlock our front door when the internal key is still - another important and well-functioning feature.
About getting used to that now cross standing castle, in which you have to but only habit that the key is to keep up transversely to the door edge, but this seems to be the case with all these AC / locking cylinders well.
Summary: I would recommend it highly, and our front door is again safe ;-)