I supply ITFS from 70+ countries. Yes, Italy is the most expensive ITFS in the EU. I would recommend setting up a local number from Italy to give very competitive calling card rates. I think they artificially keep the rates high just so encroaching calling card operators can not compete on a level playing field. Setting up a local number that will point to your CC platform in UK is easy enough. I would only do if if you agree to pay all the monthly fees.
James W. Wilson
james (at) downetworks.com