You don’t get speed awareness courses in Scotland, there are loads of plod on the M74 and they don’t seem so tolerant of 90MPH German-wagons, so I think most people slow down a little when heading North.
My mate ended up on a speed awareness course in Carlisle.
What’s the point of speeding, anyway? Even aside from the legal/environmental reasons, it barely saves any time anyway.
Should round it up to 120 km/h to be in line with most of Europe. (Seems to vary from 120 – 140 km/h [excluding the “free” parts of the autobahn in Germany] IME).
I think the French were considering dropping their autoroute limit from 130 to 115 (=71.5mph) though, and they’ve recently reduced the N-road limit from 90 to 80.