Custom Single Post Type not referring to single-post-type.php File

I’ve defined a Custom Post type called “Press”, I’m trying to modify the Single Posts template for that Custom Type. The single posts custom file is called “single-press.php”

I’ve tried using an if in_category(cat_number), get_template_part type statement in single.php & it seems to give me a White Screen rather than the page …

This is the code I’m currently attempting in my single.php file:

<?php get_header(); ?>

<div class="row">
    <div class="col-sm-12">
        <?php get_sidebar(); ?>
    </div>
</div>

<?php if in_category( $category, $_post )  {
    echo('Category')
}
?>

<div class="row">

    <?php if (have_posts()) : while (have_posts()) : the_post(); ?>

        <div class="col-sm-8 col-sm-offset-2">
        <article <?php post_class() ?> id="post-<?php the_ID(); ?>">
            <?php   if(has_post_thumbnail()){
                the_post_thumbnail('large');
            };
            ?>

            <h1 class="single-entry-title"><?php the_title(); ?></h1>
            <h2 class="subhead"><?php the_field('subhead'); ?></h2>
            <?php include (TEMPLATEPATH . '/meta.php' ); ?>

            <div class="entry-content">
                <?php the_content(); ?>
            </div>

        </article>

    <?php endwhile; endif; ?>

    </div>

</div>

<div class="row">
    <div class="col-sm-12">
        <?php related_posts() ?>
    </div>
</div>

<?php get_footer(); ?>

Does anyone have some suggestions as to what might be going wrong, or how to get the Single “Press” posts to follow what’s in single-press.php ??