Sorry, it gets even more complicated. So university entrance requires specific credits in english/maths. But NCEA has numeracy and literacy skill requirements but you don't have to get those credits specifically from "English" or "Maths" subjects. So for example you can get your reading/writing/maths credits in the Geography class. However, this is based on which standards your school has picked, as there is flexibility over which assessments under each subject they will teach.

Sorry if what I wrote was misleading, I'll edit a little to clarify.

Also, you could pass NCEA Level 1 on unit standards alone. Iirc these didn’t have end of year assessments, were either pass/fail (not a achievement, merit or excellence like the achievement standards) and if you had a pulse and / or could write your name, you were likely to pass

Unit standards were a non-exam way of assessing. Exams were sent to other schools to be graded, but I'm not sure that is the case with unit standards. Probably the teacher has a lot of discretion. Also, if you were in NCEA 15 years ago then it was still pretty early days I think. I presume it's been refined over time.