In all fairness, I wasn't unwilling, just trying to cover my bases.
With that, I did the reboot as suggested. Wow, what a bit of a hot mess, but I think it is something I can work with.
The challenge is that it moved ALL of my contacts and calendar items to the iCloud folder and duplicated everything. So a bit of a mess now to clean up so it is only showing single items for each.
Lastly, anything you can share on how to stop my Outlook responding like an old dog. It now takes an extended period of time to switch between Mail, Calendar and Contacts etc. (and please don't suggest getting a Mac - 😉)
All in all I appreciate your time to reply, it did get me further along than all my efforts before.
Cheers, Adam