Building inquiry - What should be considered? Tips and suggestions?

... We just went through this ourselves. Otherwise, take a look at the building regulations; they also contain some requirements for the preliminary building inquiry (documents, etc.). We needed an authorized person, then we submitted our preliminary building inquiry with exactly one question along the lines of: "Is this house, at this location, approvable?" We were strongly advised to phrase the question as definitively as possible and thereby receive a "yes" or "no." Anything else could lead to a rejection, especially if it is as specific as in your case or ours was.

Good luck!