For 35 years I have thought that this trade needed licencing/regulation.
To do my part I spent a fortune on BS5750 and then ISO 2002, was a member of AA appointed garages, A Bosch service agent and then Bosch Car Service, Member of Motor Codes, all mt staff trained in gas handling requirements (remember that?)
It took me 35 years to realize that it was all a total waste of money, everyone efficient in sending invoices for their'policing' but doing absolutely nothing to improve our Industry.
I for one see no benefit in yet some other half baked scheme being suggested.