Like any good political gains best achieved, it is better to approach these authority entities as an organized group. They may ask who you represent, or are associated with. When two or three show up to a meeting representing at least in their theory even more, you get to the top quicker and a more respectful relationship can be achieved. They like it when you do all of the work for them. They like it when you make them look good. They like to hear that you are in attentive concern to their position. After they have dealt with a group a few times, the nudity is a more usual thing and a single person as an event is not so unusual, nor any big thing.
That is a hassle just to take a naked hike, but it would change things for the future for more than just yourself.
I have thought to contact the police to get a training, so that the law is clearly defined, they are not reading things into the law, or making assumptions, when they encounter some situation with nude people. Here to break the law you have to expose genitals, or nipple area. A "reasonable person" might be "alarmed", a complaint needs to be made by the offended, which may require them to be witness in court. Without those understandings, a cop might haul off someone in their own yard oblivious to others as a sex offender and it has to be hashed out in court, or thrown out, or in the least take everyone time, money and energies.
In your country, isn't it also necessary that police have a clear idea of the law and departments have established policy to consistently guide officers in the field? I would assume that something similar is the cause of your concerns, that you would consider speaking to the police first. You are probably in a situation that is new ground, if you contact authorities, so if there is someone with experience, they would be unique in their experience and your experience may be different.
Jus' sayin'
Jbee