Were in the UK and no, Costco don't do holidays here - mores the pity!
Having booked ourselves previously, we have done the DU thing for the last few cruises, taking advantage of the 10% discount for booking on board and the OBC from both
DCL and DU. However, each time we want to book something, it's a black out, so we can't use the discount, however DU will still give you OBC for booking direct, the amount depends on the price of the cruise, I think the amounts are on their website.
This time however, we found a UK agent, who have given us a cheaper rate, even with the OBC taken off that we would of got from Dreams, so we went with them, I think we can transfer the booking to them too.
The UK needs a Dreams agent over here, they would clean up, it's a pain to have to wait until lunchtime for someone to get back to you, as you have been thinking about something and get on to it first thing in the morning.
I will,offer my services, used to be in travel...... Now there's am idea!