Certainly the choice of direction gives the best chance of a favouring wind, which (if it happens) will make a huge difference to Skipjack's state of mind! Just to put guest back in his box and demoralise skipjack, the estaimate of 8mph assumes more than 12 hours of riding time. That's tough whatever speed you're doing. More likely the gallant fellow will take food and comfort breaks, pushing his required average to 10-12 miles an hour. If he and finish up averaging nearer 12-15 miles an hour. And if he's not familiar with that route described by Eric, he's quite likely to wander off course, given that an hour at least will be done in darkness. So 2-15mph is going to make him feel more comfortable about getting on that ferry (less comfortable in every other sense).

Having been there - well 962 miles from Land's End to John o'Groats in 11 days - I think Skipjack's effort is well worth 5p a mile. (Am I really the first to put my hand in my pocket?) Of course, Skipjack won't have the crippling haul out of Lyme Regis, Harston Pass, the roller-coaster A68 up to the Scottish border, and the phenomenal climbs twixt Braemar and Tomintoul. But also he will have sod-all shelter from the wind, if it does happen to kick up from the wrong direction.