I enquired about a trip to Denmark by ferry and they could only confirm the cost/points over the phone if there was availability on the dates I wanted so you should probably give them a call.

For the trip I enquired about (June, UK to Denmark return) was £686 with car and 2 people, inside cabin to Denmark or 121000 Avios or £350ish with 62000 Avios

If you get a cost in Avios points it would be good if you could update the thread.