A Microsoft file hosting and synchronization service.
Dear SimonGrantA,
Thanks for participating in the Microsoft Community. I'm an Independent Advisor and I'll help you.
You could try a Onedrive reset:
-Open a Run dialog by pressing (Windows key + R)
Copy this and paste it into the dialog window then press OK
%localappdata%\Microsoft\OneDrive\onedrive.exe /reset
then, run same command without /reset
%localappdata%\Microsoft\OneDrive\onedrive.exe
next, verify the status of the files.
For further information see below link:
https://support.office.com/en-us/article/reset-...
Do not hesitate to ask if you need more information.
I hope it has been useful to you.
Regards,
Renzo.