Last summer on my way to Folkestone I did M74, M6, M6 Toll, M1, M25 then M20. I left home at 7pm expecting to arrive in Folkestone at 0430 / 0500 depending on traffic. Instead I arrived at 0210 and slept in the car until the first tunnel crossing in the morning.
Distance is just under 500 miles so I was quite happy.
I’d avoid the A66 at night as it can be rammed with trucks, they are about to start construction work on the A1 just south of Scotch Corner. If those works are any like the ones further south were then it’ll be bedlam and well worth avoiding.
M74, M6, M6 toll (it’s well worth paying for) is the way to go.