hi buttons ,i think you readit wrong .fitting an a frame to a car makes it a trailer with brakes fitted regardless of weight. and they must work.
some dont use a sliding hitch and use other means of applying the breaks .electrically or hydrolicly or air. these do meet the requirements so i dont think we can actually generalise and say aframes are illegal.
there was one at malvern last year controlled by a nintendo ds contraption very nice .i liked that one.
Sorry VW I am getting into something that I know absolutely nothing about. I just found cut and paisted, however the quotes appear to throw some light on the legality or not of A frames .
Are you saying that as a braked trailer they are not required to conform to European Directives contained within the Construction and Use Regulations?