This may sound a stupid question, but in theory at what time of the night would they be most visible? Yes I know it’s during hours of darkness, but due to the earths rotation is there a ‘best’ time? For example just after sunset or just before sunrise, or the middle of the two?
I think the quick answer is No, beyond the fact that you need a dark sky: the timing is basically random, dependent on when the "storm" from the Sun gets to the Earth. It's not like seeing meteors - since those are caused by the Earth sweeping through a volume of space, being on the side facing "forward" means more meteors on average, so the period between midnight and dawn is best.
If you'd like some warning, keep an eye on AuroraWatch UK:
https://aurorawatch.lancs.ac.uk/ - if the number on the main "Activity plot" gets into the red zone, there's a good chance of the aurora being visible after dark somewhere in the UK, with higher numbers typically meaning it's visible further south. Note though that this is a record of actual data, not a prediction - it's just the fact that it varies on a scale of hours that means once it's high it's likely to stay high for a while.
My son got some spectacular views over Loch Lomond whereas I - in the Clyde Valley - had to make do with a slightly chromatic glow to the North. Having said that it transpired that the full shebang was visible directly above and if I'd just gone out I'd have had a ringside seat. I always laboured under the impression that the lights were always visible in one's Northern sky. Hopefully they'll be on again tonight.
That very much depends on the intensity of the event - the more powerful it is, the further south the 'active' part of the sky is. So, yes, typically in the UK the aurora is visible somewhere to the north, but with a particularly strong event it can be overhead, and that's more likely the further north you are. Even in Cambridge it was reaching up near to the zenith last night. Good luck for tonight!
