I think I had better so in and look at the Oct 15th on the Diamond. Istanbul is one of my major resaons for picking this itinary - plus the added bonus of Priscilla & John.
I spent 20 days on the Diamond doing a crossing and loved every minute. Maybe it helps that I have a room all to myself but didn't heard any of the couples complaining about being on too long in a small space. Probably because we were all having such a good time. That many days it becomes like a family.
Just looked. The Diamond cruise on the 15th still lists Istanbul as the port of embarkation.