Ratfink, I used to sling the bike over my right shoulder... the new technique is to put it accross my upper back, leaning on both shoulders. MUCH more comfy, as the weight is balanced evenly accross your back and you can walk streighter with it. It does bounce a lot while running though, but I doubt I'd do much of that at Three Peaks
Lilac, you have to carry one of those orange plastic bivvy's. I have a better one, but they insist on that large heavy pastic one. Depending on weather they may make you take a waterproof as well, and you need to carry a whistle. Mine is incoporated in my rucksack. That is it really. I carry gels and bars to keep the energy levels up, have a waterbladder in my rucksack, as there is only one waterstation (that you HAVE to walk through) going up Whernside. I also carry a multitool, chaintool, spare chainlink, a couple of inner tubes, a pump a spare cleat and spare cleat bolts. I have a friend (Dominion) doing my support and he has spare wheels and outer tyres in the car with him as well as more food and drink just in case, but I haven't had to use any of that before...
I go very carefully, so not had any wheel/tyre mishaps... I think you are quicker when you take it carefully enough not to have any mechanicals rather than going fast and get mechanicals, but that is my excuse for being a chicken off road really LOL