Thankyou for the replies which have raised my confidence greatly.
We have changed our flights to a day early and are planning to book a hotel near the Piazza Roma, so that we can have an afternoon, evening and morning in Venice, before a hop skip and jump to the ship. Any advice on a hotel near the Cruise Boat Docks at PiazzaRoma would be greatly appreciated.
Luckily we have found the Lonely Planet guide to Bari, inc maps, which although at first we thought it an odd port, it seems like it may be a whirlwind to take in the clustered together sights worth visiting (memories of Rome come flooding back now, too many ruins, not enough hours)
Thankyou so much KATE 52, for your information on Istanbul and the Sultanhammet area recommendation, duly noted and searching already.
The advise on the lire problem was also greatly appreciated, it may be worth trying to get these prior to the visit, if possible.