Ferry routes have really taken a pounding in the UK over the past decade or two unfortunately. Combination of the channel tunnel and low cost airlines I would making former routes uneconomical to run is, I would imagine, where the majority of the blame lies.

One example: I've always wanted to do a motorcycle tour around Scandinavia, particularly Norway, but it's a heck of a ride from Calais all the way up there. For many bikes, far enough that you'd need to organise a service and tyre change at least once whilst on the trip. At the time when I was first thinking about this I had a bike with a 3750 mile service interval, although I could generally squeak 4000 - 5000 miles out of tyres.

So my plan back in 2014 had been to ride up from East Anglia to Aberdeen, get on the ferry to Lerwick, and then get a ferry from Lerwick to Stavanger in Norway to cut off a lot of "transit" riding. Unfortunately it turned out the website with this ferry route listed was lying to me, and that actually it had been retired in something like 2008. (You can still find this route listed on some websites today, but it's long since gone.)

Nowadays I'm not even sure it's possible to get a ferry from the UK to Germany. I've never done it but you used to be able to get a ferry from Harwich (very convenient for me) to Bremerhaven: no more, sadly.