Remove action within a class in a parent theme’s includes folder from the child theme

Thanks a lot to Nathan Johnson:

The solution was to use instance of the class the action was defined in.
The class was globalized in the theme after instantiation.
So the adding the below code to functions.php of a Child Theme worked:

function remove_woo_forms_hooks() {
    global $woo_a;
    remove_action('woocommerce_before_customer_login_form', array($woo_a,'before_customer_login_form'));
}

add_action( 'after_setup_theme', 'remove_woo_forms_hooks',0);