northern italy is not known for its rental yields or appreciation. Its a mature market really for a buyer who is going to enjoy its other qualities.
You would be looking at 12% VAT, stamp duty which I think was 1.5%, land tax every year roughly .4%. Rental income would also be taxed. I wouldnt attempt avoiding that as you have a special police force in italy specfically for tax evasion
ANYTHING the italians say take with a pinch of salt (ie we will manage no prob, you will get X yield, lying is part of their business culture, and if you look down through their history in general its the same....
All that aside, Florence is one of the most beautiful places in the world!
Mortgages by the way are Barclays I believe