Hello Sloots. I have been playing with your .map file. Please try this.
Open up Drawing.
In the Info pane under the Component tab click on the projection button (compass). Pull to "Repair Initial Coordinate System" and choose "More..."
Click on the "Custom" tab. Next to the Base setting, click on the globe-projection button. Pull down to "More...".
When the Base Coordinate System dialog opens, click on the Standard tab. Select "Amersfoort" from the list below. Note that this doesn't have a EPSG designation next to it.
I think you will find that the datum change will adjust your existing point correctly to the middle of the tower.
There are some subtle changes from these two Base systems.