'Fraid I won't be able to come, so please redistribute my place to someone more deserving. Sorry to be a crank!
No prob, I've allocated your ticket to someone else. See you tomorrow

- Do I need to bring an extension lead/4-way? (Only got great big things with long cables, and I'm aiming to travel light)
If you have one and can bring it along, that's cool, but we can probably accommodate

- Which network is most likely to get a usable 3G signal? 3 or O2?
Terry confirms that O2 works ok. Perrin uses 3 and says it's ok. So I'd say either's good.
- Security - we're all bringing laptops'n'stuff - have there been any problems with gear 'disappearing', I'd like to hope that we're all a trustworthy bunch - does everyone generally do a good job of looking after each other's stuff?
There haven't been any problems in previous years, and I'd be surprised if there were this year. However, I can't take responsibility for what terrible things might happen to your belongings.
(Are laptop locks and stuff unnecessary, or worthwhile?)
I don't know what they are.
- Laptop, well prepared with *everything* installed (Including documentation etc, in case internet access isn't too good)
Yeah that's a very good idea.
Or what about things that are essential to leave at home? (big speakers, huge monitors, etc... - looks like space is going to be fairly tight? - I guess I'll leave my Wacom at home, but hoping there's just enough space for a mouse, as I can't stand my laptop touchpad...)
You can probably find place for your wacom if you want, but I'd leave other peripherals
