I always stick with boots because I've damaged ligaments in my right ankle so much from playing around with different extreme sports, that the slightest awkward twist can cause me agony. So, if you want to protect your ankles I'd go with boots. Also, with footwear with no ankle protection, its easier for little twigs, thorns and stones to get into the shoe, or caught in your sock which can be a right pain.
Regarding poles, I prefer not to use them because they turn out to be a hassle if you have to start scrabpling over some rocks. They're always a welcome help on a long, straight downhill section with no real obstacles, but you're not really going to find that where you're going.
Also, time is of the essence, so I guess poles would be more of a hinderance than a help- you may find yourself running/sliding down the shingle of Scafell to meet your 24 hour deadline, in which case, poles wouldn'treally be of any use...