the company is norse merchant ferries baz and heres a link to their site
Norfolkline Irish Sea Ferry Services sailing from Irish ports Belfast and Dublin and English ports Birkenhead Liverpool and Heysham offer passengers and freight customers a reliable daily ferry service night and day across the Irish Sea, these prices are only cheap on the 10am morning sailing, i priced the 22:00 pm sailings and its in and around 200 sterling, so price it for maybe 10 am friday returning 10am sunday or monday, the crossing time is 7 hours on the button, cabins in the boat are an extra 30 quid, the car deck is visible from the lounge so you can keep a watchfull eye on your pride and joy... also im just heading back to my own place jay so i'll pm you those details soon as i get in