Hi Patrick,
Thanks for the reply but this did not resolve the issue as I already had those security settings applied.
Turns out I had to change a registry key (to alter a setting applied by my version of Office).
I had to set the signinoptions key to a value of 0 (it was set to 3) under this reg key:
HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Common\SignIn
then Onedrive then synced without the error message.
Thanks anyway,
Chris