This was a breeze as we missed our flight and with it the original embarkation point at Savona. We eventually joined the ship at 2nd port of call at Barcelona. 10 mins after we produced our tickets at the security desk at the port we were in our stateroom. The bags arrived 10 mins later.
Only thing to add to this that is relevent to the review is that after we missed our flight we contacted Costa who were very helpful and understanding, and arranged for us to join the ship at Barcelona where they were expecting us when we arrived.
We had a balcony cabin that was pretty much as perfect as you can get. Could have done with a few more English TV chanels.