The spot is deliberately unmarked, so people walk right past it. Here is exactly where it is, what you will actually find, and how to walk there.
iThere is no bunker to go into. The site today is an ordinary residential car park with one small information board. That plainness is a deliberate choice, not neglect.
Walking there from
Pick a start point above to see the walking line and rough time on foot.
Tap a numbered point on the map to read what is there now and what stood there before. Orientation map, not to scale.