I don't see many options there. If your neighbor insists on the 2 cm, then the bushes have to go. (which he will probably do on his own) Because I wouldn't allow such a neighbor to cut them from my property.
So what next? The best would be an agreement between neighbors over coffee. Ask him what the best solution is for him. If necessary, buy those few centimeters from him, or register a construction easement. If he insists on a rollback, then pass the ball to the company that built it.... their problem, their cost. Plane it down, cut it off with a grinder, whatever.
You could also have a surveyor come again to measure his L-bricks. No one places the centimeters exactly on a boundary. There are always a few millimeters of deviation. In case of emergency, just let it come to a lawsuit. If I understand correctly, it's only a few meters that protrude by a maximum of 2 cm?
Neighbors can really be a great luck, but also a huge misfortune.