I just sold my TDR to the IOW. Courier (Mike K) dropped it by the ferry, new owner pushed it on to the boat & rode it off the other side. I'm sure you could arrange the same in reverse. Saves the cost of a van on the ferry.
Take the ferry over as a foot passenger (about £10) and book a return for you and the bike (about £25).
RD 350 LC - 1982 - bounty like my bike in the 80's, finally got an original UK one. 31K/Aprilia RS hybrid - ex Yogi and Muttsnuts bike - my first hybrid Triumph Street Triple R (sorry!) ...and a box of bits I hope to be able to turn into a 1983 31K