Desktop disappeared, Finder repeatedly crashing

Hi

Late 2014 iMac 5k

4Ghz, 32GB memory

macOS 10.13.2

Since installing the latest update this morning, my iMac has a number of problems:

1. The desktop is not showing any icons;
2. In Finder, the folder that used to be simply called "Desktop" is now called "Desktop - Guy's iMac" (which does in fact contain all the items I expect to be there, they just don't display on the actual desktop);
3. There is a folder called "Desktop" in my Documents folder which wasn't there before, containing what was on the desktop prior to the update;
4. Finder is crashing repeatedly and having to be relaunched.

I'm guessing that somehow my desktop folder got moved and then recreated where it was supposed to be as part of the update?

I've tried the very basics - reboot etc - is there a plist or other file somewhere that I can delete to force the recreation of the desktop correctly? Obviously, simply trying to rename the folder doesn't work.

Many thanks

Kind regards

~Guy.