We have not booked any "official" shore trips as we are happy to travel independantly. Istanbull and Athens are easy to do without joining an organised trip. After checking the 'net I also think that Pompey will be easy as it is very close to Naples. I read a review written by someone who had been on the cruise two years ago. For the visit to Florence they shared an air con. taxi with another couple, which worked out better value than the organised excursion, they were also taken to places off the tourist track. They also advised against going to Pisa as it is a tacky tourist trap.
Please note that the correct address for my photo album is:-