70 miles each way on the M25 at rush hour is surely 4-5 hours a day of driving?
I genuinely think this will be the case. My manager commutes from J15 M25 to somewhere near Leyton (J27 M25) and it takes a minimum of 1.5 hours each way if all of the stars align and he leaves home at 6am. Some days it takes him 3 hours to get to the office.
I do a 15 mile commute (9 miles on the M25) and it can take me up to an hour when I leave the office at 16h00.