Naturally when the police speak with one they like to ask for one's name and date of birth. And one would probably expect the police reporting procedures as a matter of course to require date of birth and name as a prerequisite of accepting the crime report for example the metropolitan polices online crime reporting portal may well be programmed like this.
But what is the legal situation? Are they required to accept and look into a crime complaint/report made by a member of the public who declines to identify themselves?