Clear Phone Number History in Messages on Mac

Hello,

I am trying to find a method of clearing the phone number history that appears in Messages on my Mac Book. I am really sorry if this is a simple solution and the answer has already been posted unfortunately my searches came up with nothing that works. When I click on the search bar in Messages there are 4 historical numbers displayed, these numbers are not in my contacts and never have been, I don't actually have any stored/saved messages at all. This has been annoying me for quite some time, these numbers do not appear on my iPhone and I recently reset my Mac which cleared the list but it was repopulated after I had received a few messages from numerous places that are not in my contacts list (verification codes, appointment reminders, one off calls etc.), this suggests that the numbers/history is sitting locally on my Mac and not the cloud. If I select the number it will appear in the 'to' field and then I have tried going across the the 'i' icon in the circle on the right but there is no means of removing the number from this 'recents' area. I have also tried going into Siri and Spotlight and deselecting everything under what appears in search results but it made no difference. I have also tried going into ~/Library and deleting the whole messages folder (which repopulates) as well as the contacts folder but neither has any affect. Would love for a Mac guru to give me a solution. Thanks.

Screen shot below for clarity.

[Image Edited by Moderator to Remove Personal Information]