Apple Maps shows a spurious Home address - Help!

I have been having problems getting Maps and Siri to show my 'Home' address correctly. I have now deleted my personal contact card and deleted all Siri history on all four devices (MacBook, iPhone, iPad, Watch). But when I search for 'Home' in Maps, it shows a red marker on another house in the street. How does Maps know what 'Home' is, since I have deleted al references to it, and why is it showing another address in the street? How do I delete this incorrect information and start again? Any thoughts of where I might start investigating?