I worked for a company once who dealt exclusively with UK address data. We compiled it from dozens of sources then cleaned, organised it and became a reputable

I worked for a company once who dealt exclusively with UK address data. We compiled it from dozens of sources then cleaned, organised it and became a reputable source of truth. Our end clients were large companies, such as utilities/marketing, who sent in their (incomplete/wrong) data - and were provided with healthy data. Such data was used for validating buildings, for example a gas company checking for fraud or voting registration. I learned a great deal about something so often overlooked!