I tried to go in to My OSMC to perform a manual check for updates, but was greeted with the “Add on error”.
Please see the kodi.log here: http://pastebin.com/hLSTtjJJ showing some sort of Python error
I rebooted the Pi and tried again and it worked, so I’m not sure what the problem was?
Before this, I had rebooted the Pi via SSH after not touching it for a couple of weeks. It was running headless - I guess it might have downloaded updates from before and was waiting to install them. It doesn’t seem to install them by virtue of just rebooting. Not sure if that caused the add on to get confused but thought I’d report it anyway.