Thanks for your kind words everybody.
I've only seen two aurora so far, having only been living in Christchurch for 7 years and only getting back into astronomy in the last year. This was definitely quite a lot brighter than the previous display I saw on 15th July 2012.
I worked out on the night that the ideal fov would have been about 60 - 70 degrees to capture most of what was visible, but it probably spread out wider than what I could pick up with the naked eye.
With the 50mm on my APS-C camera I work out I get around 30 degrees. I'll keep saving my pocket money and maybe I'll have a wider lens for the next round
