The changes were being made in a stylesheet that is auto-generated by the parent theme. In the specific case of the Cherry parent theme (which is widely used in templates sold on themeforest, templatemonster etc), you cannot make stylesheet changes in reserved files such as main-styles.css (Despite them existing in a child theme).
The solution is to either make style changes in the style.css, or to make a stylesheet with a dependancy on main-styles.css, in order to override any auto-generated styles.
I.e.
<?php wp_enqueue_style( $handle, $src, 'main-styles', $ver, $media ); ?>
Can read more about the solution here:
http://www.templatemonster.com/help/wordpress-cherry-framework-keeps-reverting-my-css-changes.html