WooCommerce Show Change From Default Quantity In Cart

Not getting any joy on this through Google so hoping for some guidance here.

Using WooCommerce Product Bundles, I've got some product bundles comprised of variable lines, with mins of zero and infinite maxs (with the idea being that customers can choose to either not purchase that bundled product, or as many as they want).

I've got default quantities set with the below snippet found at http://somewherewarm.gr/:

add_filter( 'woocommerce_bundled_product_quantity', wc_pb_default_product_quantity', 10, 4 );

function wc_pb_default_product_quantity( $default_qty, $min_qty, $max_qty, $bundled_item ) {

/** Below code is copied and edited for each bundle & bundled product */
  if ( intval( $bundled_item->bundle_id ) === 32 && intval( $bundled_item->item_id ) === 1 ) {
    $default_qty = 6;
}
    return $default_qty;
}

Currently if a customer zero's out a bundled product, that product disappears from the cart. What I'm looking to achieve is something like this (with the below example having a default quantity of 2):

Product ABC | 2 0

I'm also making an assumption that whatever appears on the cart is what will appear in the New Order emails that WooCommerce send out, which is where I really need this info to be.

I really don't know where to start with this one, and Google has yielded no results.

Thanks in advance.