Just seen BritNick's 2012 report and photos. Those race shirts are a bit on the outrageous side. All mine seem to be black, grey, or sheep poo colour.
brer - so you're actually running a 24-hour race? Excellent. How many miles do you think you could do? An aim for many is 100 but it's a tough call.
In terms of training it's basically marathon training and then for extra time on your feet there are two schools of thought:
1) Build up long back-to-back runs - to ultimately day 1 30M, day 2 20M.
2) Single very long runs, but note there is very little if any training advantage beyond 40 miles. A good way of doing this is entering a couple of ultra events.
I favour method 2) but most it seems use 1) for which I have come across a good schedule - I'll see if I can find a link to it. To give you a taster the final week is: 4-3-2-rest-rest- (OK so far?)-100-rest.
You'll need to consider nutrition carefully and start eating immediately, right from the outset. And consider electrolyte replacement (BritNick is the expert on that).
I'll probably be doing this new Cotswold Way event in September which is 100 miles.