What is the best way to get from London to northern Poland without flying ?

I am accompanying an 85-year old man back to Poland to see an old friend. He's in excellent health but he hates flying. I am trying to establish the best way for us to get there - car (if so which routes?), ferry (likewise), train, a mixture of these, etc. Accommodation suggestions or approaches would also be very welcome. The final destination is a town about 160km south of Gdansk. Many thanks for any and all suggestions!

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia��).