Seadream was a dream for us - we found it in 2008 and now in 2012 we found the right combo of airline tickets and Seadream Cruise to our dream destinations.
We were very excited, and we also made sure Seadream was informed about food allergies. This was not a problem we were told, and I am happy to write that it was not a problem for us. However one passenger had nut allergy and suffered an attack one night at dinner - not that good...!
We were also very eager to learn things like dress code and so on. So when we got the travel documents we also read that it was a rather relaxed dress code - boy was we wrong, but we managed to fix that somehow ;-)