have you tried phoning eurostar and booking hotel and train,their prices seem very cheap,but you do have to buy park passes seperately. ps,do phone eurostar because i think their website is very confusing.Itried to book a train on their site and it kept saying no return trains for the dates booked,so i tried a return date a day later and then it said no trains on outbound journey,so i phoned and booked original dates,and the lady told me there was plenty of seats available.