I would see those parts as just explaining the law, where the law is a separate thing, rather than defining the law. Maybe that’s just splitting hairs, though.
Magistrates will take the above as Law, its one of those grey areas of law, so selective application of the law exists, and thats before you even get into a debate of whether you have a say in the laws that you are born under if you havent moved abroad.
No, you're right. Those sections are included in the Highway Code to inform drivers, but it's not the placement in the code that makes them law - that's the original Act that the Code refers to.