Could you try commenting out the changes in /boot/config.txt and running:
curl -sS get.pimoroni.com/unicornhat | bash... it should reimplement some of the changes @sandyjmacdonald recommended mind you, I just want to go back to a state closer to a freshly imaged Raspbian.
Once done, if it still does not work then please post the content of your /boot/config.txt
