It does not take hours to change a law, but it is very quick to ignore a law and mow down a field. Now, whether the law will prevent them from doing that is a different thing. Someone would have to notice that they're going to build in a protected area, notify the police and contact them officially to notify the error.
At this point they may still ignore that, then you'd likely have to start a trial. If you're lucky and you start the trial before they mow down the field, they'll likely agree they made a mistake, pay for your lawyer and move to the field besides.
There's no need to change a law to fix something as simple as paying a couple lawyers.
Generally grapes used to make wine are not really great to eat.