If that’s so, why do you think the byelaws have not been thrown out over the course of their 13 years of operation and innumerable prosecutions?
Do you have any evidence that any such challenge has ever been attempted? If not, I would suggest that is the simply reason - the matter has not arisen. Such Byelaws had "existed" for many years in respect of the cases I cited (and others) and yet they were still declared
ultra vires, as they always had been.
The fact that a challenge has not been made is probably more likely to be a factor of the relatively low number of prosecutions (in comparison to other offences) and the fact that in many cases the defendant is likely to want to get the matter over and done with with as minimal stress and cost as possible.
Very, very few people fall into the category of being accused of a Byelaw 18 offence - and there being no suggestion of a RoRA offence - who then also have the time, effort, willingness (and, crucially, the money) to defend themselves properly and to fight the unlawful prosecution they are facing.
What I do know is that if I were ever to face such a prosecution then I would absolutely engage this defence. It is unacceptable that people who, in many cases, have no malicious or fraudulent intent are able to be criminalised.