In reply to TobyA:
Generally a skinny steel fork like on the Croix de Fer will soak up more vibration that a wide bladed carbon fork, but it's not a black and white issue. You can certainly get comfy carbon forks and harsh steel forks, I've had all the permutations
But it's not so much the fork that will make it more comfy as the frame - the thin walled, large diameter alu on the Boardman with gernerally make a stiff and responsive frame, but it might also be a bit harsh on the bum (especially on a long day out). The Genesis is likely to soak up a lot more between wheels and arse, but it's likely to not feel as stiff and responsive as the Boardman (and it's almost certainly a bit heavier).
Just remember with either type of fork and disks not to look down when you're braking - you can get an alarming amount of rearward flex when you combine disks and slender forks, particularly on tarmac. Not something to worry about, but disconcerting when you see it nonetheless!