UnicornHat not working

Hi Guys

Being gifted a UnicornHat for my birthday I am eager to get it running. I fitted it to a Pi2 and fed it with a 2A PSU. I installed the libraries using the curl script and, with bated breath, I ran simple.py - instead of the expected cheery magenta glow I was treated to a blinding riot of psychedelic colour. I modified simple.py to be even more simple:

#!/usr/bin/env python

import unicornhat as UH
import time

UH.brightness(0.001) # I don't have welding goggles

for y in range(8):
    for x in range(8):
        UH.set_pixel(4,4,255,0,255)
        UH.show()
        time.sleep(0.05)

time.sleep(1)
UH.clear()

and all I get now is a single GREEN LED lighting up the top right LED (assuming 'UNICORN HAT' is printed the right way up).

Is it DOA?

Thanks
Mark