Any question answered...

if you were gonna do that drive and could choose when to leave to avoid the bulk of the stop/start shit but wanted to arrive in Newbury as early as possible, when would you go?

What's the starting point? What's the earliest you can set off?

The trouble is, it's so unpredictable. I've done W1-Slough in under an hour at all sorts of times, but equally taken 2 hours at any start time from 3pm to midnight.