This thread does neatly illustrate one of the hazards of using online portals to look things up - particularly legal things.
We have an extensive quote above, which is from a piece of secondary legislation dated 2015. Clearly this is not going to have been applicable in the 1970s.
The danger, however, is that in many complicated pieces of law (the tax code, for instance) amendments are often made to the wording of the old legislation; and the online portals want to give you the current version, so they amend it. Which is fine if you want to know what the law is now; but not if you need to know what it was then.
I used to have on my shelves the annual volumes "The Taxes Acts" for EVERY year since the 1960s, and if I wanted to know what the wording of a particular provision of the Taxes Management Act 1970 was in 1985, I would pull down the 1985 volume off my shelf, and there was the then current version. The e-publishers promised us the world, but they could never provide this facility in a form that I understood how to use.
It was very easy to use my paper volumes ...