Hi Ian. It's strange that WordPress' auto-upgrade tool doesn't work for you. I just tried it in a fresh WordPress install on a test domain, and the upgrade succeeded.
In your WordPress admin control panel, when you go to
Tools > Upgrade > Upgrade Automaticallyare you asked to fill in "connection information"?
For the plugin that's failing to move a file, you'll probably need to set the permissions on files and directories in wp-content/uploads/ to 777.
Let me know about the upgrade tool and if the 777 perm works. Cheers,