Any hints and tips for a newbie welcome.
Lights, the brighter the better (for the dark bits).
Check your bike over, bits failing along the way is embarrassing. I don't know what the worst number of punctures we've had was, but I think in October we had at least three, which was a bit of a pain. On one ride last year, we had two punctures just getting out of Gatwick Airport (carpeting is clearly bad for tyres!). I am as guilty of this as anyone, I had one puncture on a FNRttC last year, and on inspection, the tyre was damn near bald. I also noticed that a brake cable was about to break, but careful braking for the rest of the ride obviated having to deal with that.
Carrying some tools/spares is a good idea, but someone else will almost certainly have stuff. Just don't rely on it. I normally carry a good pump, two spare tyres (700C, so if you're on an MTB I can't help), a puncture repair kit, a spare brake cable, cable ties, lots of tools. They'll still be things I can't deal with though.
Carrying water, even when it's cold, is a good idea. Over an entire night the chances are you will get thirsty, even with the mid-ride stop. If you do have a fall, clean water is useful to clean a wound out!
Some munchies are also a good idea, for additional energy, and money is likely to be necessary for (i) mid-ride stop (ii) breakfast (iii) the train back and (iv) if things go horribly wrong, then a taxi/bus/train to home or wherever.
Enjoy yourself! This is after all the idea of the ride, so bring your enthusiasm.
