Thank you, Haven't a clue, lots of good info there to think about. I originally thought about seats 50 A&B, but checked SeatGuru which said that 50A is missing a window, so it never came into consideration. As for the non-adjacent seat idea, it's looking a little less likely now. I checked the seating on BA.com and the CW seats are now starting to fill up for our flight. My partner will manage walking from row 52 to the lavatories at the front, so not too concerned about that - but thank you so much for thinking about that!
Kewbick - yes, I know it's a real long shot. I've only ever seen the aurora once before which was on a flight over the North Atlantic near the Solar Maximum back in 2001 - it was actually in April. It was particularly unspectacular. I even ended up asking a flight attendant if they could check with the flightdeck if it was the aurora. They were kind enough to check and let me know it was. It looked like a swirling bank of fog just above the northern horizon but with no colour.
At least I can say I've seen it, but I'll grab any opportunity to see it again!