Bremerhaven is one of VW’s shipment ports in Germany (you are correct, the other one is Emden), it will arrive there, be off-loaded, checked, then reloaded on another ship and sent to Grimsby for forwarding to your dealer.
Unless the ship goes to Bremerhaven, unloads EU bound vehicles, loads up again for the UK & then goes to Grimsby…
In life, it's not who you know that's important, it's how your wife found out.