I've been doing some research and haven't come across a solid answer as of yet, so I though I would reach out for a hand.
In the single.php file I have been using the next_post_link/previous_post_link as per the codex supplied by WP (https://codex.wordpress.org/Function_Reference/next_post_link).
The second I change around the code from
<?php next_post_link('%link', 'Next post in category', TRUE, '13'); ?>
<?php next_post_link('%link', 'Next post in category', FALSE, '58'); ?>
things stop working.