Quote from highways department.
"The dropped kerb area is still public highway, and as such the public have a right to pass and repass (basically you should not be parking on the crossover) but you have the right to cross from the carriageway to your property via the legally constructed access.
It is against the law to block a legally constructed dropped kerb access to a property.
The Police have power of enforcement, and you are within your rights to call the Police if someone has parked in such a way as to prevent you access or egress (the right of a person to leave a property in property law ) at your property. The Police have the power to request the vehicle be removed, or to remove the vehicle.
The only time you would not have support of enforcement is if you were crossing the public highway illegally (bumping the kerb, driving over verge, driving over footway) to gain access to your property. If this were the case and someone parked where you illegally cross, then the Police could not be involved because you would be the one acting unlawfully, not the person parking outside the property. "