Restrictions after DAS would not work. If it would come into legislation, You may as well do your A2 when possible, And just wait the 2 years for your unlimited access, as im sure has been mentioned. If this came into action, Then surely anyone who passes their car test should be restricted to cars under a certain performance grade? until they have driven a lower performing one for a period of time? Nah it wouldn't work and everyone would just drive/ride illegally. Or even if someone was to persue getting a license it'd be a massive ballache and people would no doubt be put off, Reducing the amount of riders. I have no idea if i made sense or not.