I was meanwhile trying to find out who originally developed this. The company no longer exists.
Then I called the building authority, and they told me that the building authority does not decide in which direction the angle of an angle stone is set. I have to clarify that under private law.
There is no construction encumbrance recorded in my land register, nor in the notary contract. Accordingly, I will clarify that first.
Meanwhile, I am also waiting for an offer from a young clever man who wanted to get back to me promptly.
As soon as I have clarified the formalities, I will contact you by e-mail as promised ;)