Thanks all for the information, glad to know I have the option of a simple way of getting an airport transfer at the end of the cruise.
LHT28
I cancelled O air which did include transfers and made my own flight arrangements. They were offering an outgoing flight from a UK regional airport (via a connection in London) arriving in Athens at 5pm on the day of departure.
If there were no delays or missed connection I would have had 4 hours to exit Athens airport and make the 50 minute transfer to the ship before departure at 9pm. A wonderful first day/evening and an amount of stress not acceptable in my advanced years! My TA could not get O air to give me an earlier flight even on the previous day.
I have now arranged my own flights the day before departure on the same routes as O air. My return flight is exactly the same and is direct.