Im the same. When we leave north yorkshire and join the A1 at Scotch corner on the 310 mile trek to Dover I start off just around 60. By the time I hit the M11 and then the M25 the pedal is just on the floor I get so pissed off with it.
I was the same on my long but fast journey up through Spain, France, UK n Ireland when my Santander-Cork was cancelled.
I think I wrote on my 'Spain here I come' thread that even on motorway I was 90-100km/hr, n usually nearer 90. That wasn't the case after a few hundred km!!