What's wrong with them???
You can either screw the surrounds to the car then fit the number plates or if you already have screwed on plates as shown here, you can screw the plate and the surround onto the car at the same time.
Only thing is think about securing the plates with a screw or something as they will easily be stolen if wanted.
The holder won't come out with the plate. The plates screws are behind the plates once screwed in