i personally think 80 is a good idea
providing your reactions are 20% faster than at 70
you should have to have been driving for 3 years to do 80 with year 1+2 restricted to 60 year 3 to 70
penalties should be quite harsh for exceeding the speed limit by more than 15mph with a 10mph reduction for a year for every offence on top off a fine and if your caught more than twice you are not allowed on the motorway till the third offense expires
because the third offence would reduce your speed to 50mph
in the case off a new driver [1-3 years] speeding once in year 1+2 will mean no motorway driving
and twice in year 3