Nobody can park over your driveway in a CPZ even if they have a parking permit without the risk of a fine.

The council will paint a yellow line over it which becomes depending on your view a deterrent/revenue raiser. Most people won't risk a £40 fine to park on a yellow line, whereas most people don't get fined for parking on the white H as it is not enforceable.

A lot of people will park across your driveway as they will get away with it, knowing the police don't intervene or will say wait an hour. One of my neighbours told me that a lot of people when they are caught parking over their driveway, just walk away saying I am only going to be a few minutes and don't engage in discussion or care.

These are the people who will never park in the car park even it was free because your driveway will save them 10 minutes of their very precious time.