Thanks for all the positive comments and suggestions.
For the versions I'm keeping, I've now "corrected" the slope in the palazzo shot. It is there in reality, though perhaps to a lesser degree as I don't think I was exactly square-on, but the shot looks better once everything is straightened. I've also put in a non-blurred flag in the third shot, which again is an improvement.
The first shot is going to be printed out large soon