FIlm Planning - Classification Choice

We have decided to attempt to make a film that has a rating of 15, due to the guidelines mentioned in a previous post.
Often, horror films rated 18 include large amounts of blood, gore and nudity, and these aspects of the films tend to rule the picture to attract the hardcore bloodthirsty horror audience. In recent times some films have come under criticism from film journalists, who say that the large amounts of gory violence and nudity cover poor story lines and substandard acting. This is why the film opening we are going to make will not contain stupidly large levels of blood and violence, and will focus on creating a gripping storyline and professional editing.