On the 1st January 2021, the rules regarding VAT changed for freight transport and associated services. This includes ferry routes and Eurotunnel. The new rule only affects UK based customers.
This also includes any additional services such as hazardous goods, electrical plugins, ENS (SSD) declarations and Port Passes (GVMS, PBN, SI BREXIT etc) IF added to the ferry ticket purchase.
Providing we have the customer's VAT number, all routes are zero rated for VAT.
For more information, please visit the UK Government 'Freight transport and associated services (VAT Notice 744B)' guidance page.