I think this is the stretch that starts at the Catthorpe Interchange Southbound. What they are doing is turning it into 'smart' motorway that automatically switches the hard shoulder into an extra lane at time of congestion when there is nothing blocking it. That means intermittent work installing cameras every 100 metres. However, I agree with you entirely that 50 limits to protect the 'workforce' should be lifted to 60 on Sundays when no 'workforce' is ever working.