From my own experience, the A3, M25, M1, A1(M) route is not so loaded, especially on Fridays. Though longer in length, it often turns out to be shorter in terms of time taken because of fewer traffic snarls. So, if you are a person who could afford a more comfortable journey without going through the vagaries of these long drives, you can conveniently think about a travel business class for a part of your travel.