Not going, but it sounds like a lot of fun!
DP and I are hardened campers, normally taking our vintage landrover away most winters for a freezing cold camping experience.
I would add to your list the following:
cigarette lighter charger with universal fittings (phone/stereo/camera)
Lots and lots and lots (cannot be understated) of tin foil - perfect for roasting spuds by the fire, keeping things hot, keeping things cool, wrapping things up to go away with, wrapping around dirty spatulas, the list is endless)
Not sure what the water situation will be like where you are, but we have always found a 5 litre container of fresh drinking quality water to be invaluable, even if it is just to brush your teeth/rinse with afterwards in the morning to avoid queues at the water stands
Take more than one tea towel - it will be used for a multitude of helpfulnesses and when you come to dry your dishes it will be dirty/sodden/useless
Bottle opener, otherwise guaranteed you won't be able to find a bottle with a screwtop.
Biiiiiig roll of bin bags or similar - you will need them for covering things when the rain starts, for throwing rubbish into, for sitting on (fab, especially if you blow a little air into them first for cushioning/warmth), keeping your clothes in (tents get amazingly damp with people sleeping in them and them being air tight and all)
Think that's all for now, you did a pretty comprehensive list to start with 