I can actually see in the /wp-content/plugins/woocommerce/includes/admin/views/html-admin-settings.php that there is the following if statement:
<?php if ( empty( $GLOBALS['hide_save_button'] ) ) : ?>
<input name="save" class="button-primary woocommerce-save-button" type="submit" value="<?php esc_attr_e( 'Save changes', 'woocommerce' ); ?>" />
<?php endif; ?>
Where is this $GLOBALS value set, so I can enable my save button.