EU VAT Number for WooCommerce

We had a request from a client to remove shipping when a valid VAT number is entered. We had to customise the plugin because:

1. There are no hooks available.
2. The VAT number and result of the VAT check are not stored in a session – or accessible before the checkout is complete, except in the $post data.

Would be great to store the VAT number and validity check in a session so it’s accessible elsewhere, e.g. in ‘woocommerce_package_rates’ – or add some hooks / filters to the plugin so it can be extended.