They may be other ways of answering this but the following is the method I used:
In column A write a list of company names ensure some duplication. In column B onwards write down any other information related to the company; e.g. phone number, address, email etc.
Click in the column to the right of the data and ensuring you're in the second row write the following formula:
=IF(COUNTA(A:A,A2)>1,"Duplicate Here","No Duplicate")
You can then use Tables or Filters to remove the duplicates. Hope this is helpful for any of your guys out there. Thanks for a great day all you guys at the Car Shop.