@Slick ,
@Farmer Sue Tickles am I right in assuming that they are return fares?
If so, I can well understand the toe curling reaction to the prices but I'd offer up a different perspective....
I think for both of you these are pretty 'big' events? Slick, you've convinced Mrs. Slick to go along? and Farmer Sue Tickles, this is your first big bike adventure in quite a while? In my book, these are exceptional events and should be treated exceptionally.
It's expensive, but you've both given yourselves two separate gifts.
The first is a relaxing overnight 'cruise' before landing for the foreign part of your adventure. There's a value in that. A real value. A real chance to get the 'touring heads' firmly in place, leaving the 'normal' heads back in blighty.
On the way home you've both got the opportunity of another relaxing night to let the adventure really bed in to the memory bank before reality and real life starts to take over again. There is a real value to that.
You can look at the ferries as an expensive way to get from A to B or you can see them as something far more valuable in their own right.
Good luck!
P.S. if checking out fares like that I would always use the incognito option on my browser (to stop them from tracking me).