Chris, what also might confirm the day, was what the moon was doing, Maurice says that viewing it at around 8:30 - 9:00 PM
"The biggest problem in observing this display was the waning gibbous moon, low in the eastern sky. As a result of this, I ceased watching the aurora after about an hour.'
the moon was actually waxing and 5.13 days old, edit: ( and he says it was the eastern sky - hang on?) and set around 11 pm EDIT: (if it was daylight savings time? 10PM otherwise sorry!), so if no moon was present when you saw the show, at midnight and after, that narrows it down a bit more possibly
i know what you mean by developers not bothering to print dark astro shots LOL it happened to us a few times, but when we started telling them to expect that, and writing it all over the container! they were fine