Hey Oliver,
If I'm understanding your question correctly, you're basically asking how to identify duplicates in a directory, correct?
This is the process we use:
Step 1 - get any and all information regarding current and past NAP. Get old names, locations, phones, etc.
Step 2 - run a site command in Google search for all names + city and a site command for all phone numbers
So if your business was "AA Consulting" and you were located in New York but now you're in Albany and you're wanting to check Yelp you would do these searches:
site:yelp.com AA Consulting Albany NY
site:yelp.com AA Consulting New York NY
Let's say your phone number was (324) 323-3485 but used to be (324) 524-6364 then you would add those in as well:
site:yelp.com (324) 323-3485
site:yelp.com (324) 524-6364
Run all combinations of current name and old names with locations, and then phone numbers in the site: search
Step 3 - search the directory itself. Keep in mind most directories search function sucks. It's terrible. Even YP and Superpages have a really hard time finding even just a name match. But search name and location combinations (the same ones from above) in the directory's search bar. And then search phone number as some directories allow that too.
This is about as thorough as you can get.
Also, check out Google Search Console's latest links section and see what all directories are linking to you. That could help you find dupes as well and bad information.
Good luck!
