Overall, I'd highly recommend it to anyone considering attend, it was a great event and well worth attending. From a photography perspective, it was also a great experience. To date, the majority of charity events I have done have been daytime events.
I think every piece of photography work is a learning curve, and think my feedback from this event would be the following:
1. This event had lots of low light, and I missed having access to some f/1.4's with my f/2's and f/2.8's. I think a couple of f/1.4's would probably have been helpful. I think I'll add the 16mm f/1.4, 23mm f/1.4 and perhaps the 56mm f/1.2 to my purchasing list
2. In the absence of the above, or potentially to go with it, I missed having a TTL flash which I pretty much forgot about because I don't do much night stuff anymore. I took around my manual flash for a while but a TTL Flash would have been more practical and easier as you don't have the opportunity to get second takes in most cases.
3. Dual straps like the Holdfast Moneymaker or a holster setup like the Spiderpro would have been extremely helpful. The standard straps weren't great as they are the same length and this really was an event where having access to multiple cameras would have been extremely helpful.
4. Bring a pillow. I don't mind the sleeping on concrete and the cold wasn't an issue thanks to a sleeping bag, but the lack of pillow meant I got about half an hours sleep.