Hi Philip Bryer,
Welcome to Microsoft Community.
Starting from January 16, 2025, the product team will roll out Copilot globally to Office users. Everyone has received the update. Although this update was not my decision, I sincerely apologize for the abrupt changes. I fully understand that professional users like yourself require a neat and clean working environment, and the introduction of Copilot may have become an impediment.
About disable Copilot:
In the latest version of Word (version 2501), the development team has added a button that allows you to disable all Copilot prompts in Word with a single click. To do this, please open the Word application, go to File > Options > Copilot, and uncheck the "Enable Copilot" option.
Currently, this feature to disable Copilot is only available in Word; it has not yet been added to Excel or PowerPoint, as the development team has received the most feedback from Word users. Plans to disable Copilot in Excel and PowerPoint are already on the agenda, with the development team expecting to release an update next month (February 2025) that will add a button similar to Word's for one-time disabling of Copilot functionality across the entire application.
If you have any thoughts or suggestions regarding the use of Office applications, please feel free to share them with the development team at any time by using the File > Feedback button within the application. The development team is committed to listening to user feedback to improve Office.
Lastly, we would like to extend our gratitude for your feedback, which is incredibly valuable to Microsoft. I hope the information above is helpful to you, and I look forward to your reply!
Best Regards,
Thomas C - MSFT | Microsoft Community Support Specialist