I managed 43.2 at the weekend which i'm actually quite proud of! I did my usual M3, M25, A1M route and sat with 58 on the cruise control.
Boredom reigned supreme though I was good and didn't speed up.
I usually sit between 60 to 70 on the motorways and I get 40-41 so the extra boredom really wasn't worth it in the end. I'm sure you could get even more but I wouldn't be willing to try I don't think and besides, I felt the need to drive like I was completely on fire afterwards!
Boredom reigned supreme though I was good and didn't speed up.
I usually sit between 60 to 70 on the motorways and I get 40-41 so the extra boredom really wasn't worth it in the end. I'm sure you could get even more but I wouldn't be willing to try I don't think and besides, I felt the need to drive like I was completely on fire afterwards!