My wife and I retired to Italy from the

My wife and I retired to Italy from the UK 13 years ago and are very happy to have done so.  Before leaving, we applied for and received our codice fiscali by completing a form on line.  My wife had to use her maiden name, consequently her CF was based on that.  She used that for everything including when we jointly purchased a house.  A few years later we were sent to the Agenzie dell' Entrate for our Tessera Sanitaria.  We had to produce our passports and when the official saw my wife's passport she immediately destroyed her old CF and gave her a new one based on her married surname on the passport.  We have now come to three score years and ten and are thinking about dying and how could one of us prove that the person with the CF on the catasta for the house is the same as the one on the Tessera sanitaria.  I was wondering if anyone else has had the same problem and knows a way around it that doesn't involve a lot of expense