when should I travel?

[cucumbereyes]

I am driving London to Leeds next week, approx 4 hour trip. I will be alone. It doesn't really matter what time I arrive Thursday or Friday. DC are 3 and 2. I will have help at the other end
Should I leave Thursday night after dinner and let them fall asleep in the car? Or should I leave Friday morning, they will be awake but at least it will be day
light outside should anything happen. WWYD?

traffice would be better on Thursday night if you leave 7ish - do you think you will need to take a break - if so the friday would be easier