I agree that a mandated, fully regulated scheme has got to be the way to go. If you are a rogue, you must be stopped from trading - the self regulating scheme is a poor attempt (allbeit better than nothing) at bringing in the regulation required to elevate our profession to the level it deserves.
I believe that a licence must be required in order to trade/practice in repairing motor vehicles.
I also believe that entry must be a combination of qualifications/experience PLUS an assessment, both paper and practically based. Getting in because you have been fixing cars (badly or otherwise) for years is just no good. I agree with the principle of 'areas of expertise' (diagnostics, air con, service etc..).
The assessment has to be written by real people, not those who are detached from the real world, wrapped up in a training/NQV/college environment. I have to say that in my experience, many of those who can't - teach!
What is the point of folk such as these being responsible for creating the means by which real world technicians are measured as being good or not?
The licence/points idea works as long as this is regulated, as you say, by the trading standards.
I have a fear about the IMI scheme in that it could be as much about making money (fees, merchandise etc..) as it is about raising standards. It seems to me that there are a plethora of training providers who are more interested in ticking boxes, getting bums on seats and earning money, rather than delivering relevant training to equip people to fix cars well and properly.
I have undergone a lot of training in my time, and I've got to say that some of the stuff that I was asked to 'learn' (one such springs to mind - complex harmonic motion) in order to gain a qualification, has been no good at all to me in my professional career to date. It was more about ticking boxes than being equipped to fix cars well and properly.
One of the problems of managing standards is that the person being managed can evolve from being able to perform their original function well, to being able to meet the measures enforced by one standards scheme or other (and the original functional skill is overlooked).