I don't know how much time you have between getting the van and going up North, Sue, but if you can, take her for short journeys in it, and feed her in it when you are at home, so she gets used to being in there with you. I know I'm daft but when I had mine parked in the back yard i used to take my morning cuppa out there and sit in the van, and sometimes lunch too, and the dogs loved being in it.
She'll have to be restrained somehow when you are travelling, either on a harness on a seat or in a crate. Not safe otherwise and may be illegal - can't remember.
And definitely ask the ferry company. There's P & O as well but I don't know if they do that run, they may only be cargo nowadays. We were friends with one of the Captains on the P & O but rarely see him and his wife since Sandy died, except at the occasional dog show.