Strictly speaking, I don't think there is anything legal to stop someone obstructing a driveway as long as there is no vehicle on it. You only have the right to access the highway, not your own land.i suppose the argument is you drop the kerb then its exclusively your space and no one else can use it
Maybe you could use the argument that "only if you have a vehicle on the drive then you are using the space for the dropped kerb". Otherwise, it is still available for parking.
OK, so no reasonable person is going to obstruct a driveway, that leaves about 10% of the population who won't think twice. Also, a dropped kerb space is a great place for delivery drivers to stop. It is also a passing space for narrow roads. You'd be adding an amenity.