Comment 3 for bug 227459

The issue was indeed because of not enough space left in /boot, which may have appeared obvious to some but has been part of my continuing learning experience with ubuntu.

Here is what I did in case it is useful for someone in the same boat.
I copied all the files in /boot related to the old kernel version into a folder on my /home drive and then removed each one from /boot using sudo rm form Terminal.

After removing these files I then tried dpkg --configure -a again and this finally allowed the rest of the upgrade to complete. I then ran sudo apt-get update
sudo apt-get upgrade
sudo apt-get autoclean
sudo apt-get autoremove

From what I had read elsewhere this seemed the correct process, but any comments from someone with more experience would be appreciated.

However, even after running the autoclean and autoremove commands, the previous kernel files were not removed.

Is this normal, or should they have been removed when the upgrade was completed? Otherwise I guess you end up with whole backlog of old versions and have to expand your /boot partition each time!

Sorry if this has ended up in the wrong place, I'm still learning with this whole process.