I don't get why you keep bringing up minors because they add nothing to the discussion. The UK doesn't have minors, yes I get that, nobody said it does. I'm say

I don't get why you keep bringing up minors because they add nothing to the discussion. The UK doesn't have minors, yes I get that, nobody said it does. I'm saying from all the descriptions here it appears what you call "degree" (EE, ME, etc.) is what we call "major [field of study]" in the US. Whereas in the US the term "degree" refers to BS/MS/PhD/etc. Just a terminology difference. Some colleges in some universities in the US require you to determine it upfront, some let you do that optionally, some actively prevent you. (e.g. some colleges let you take a year or more to decide whether your major is English or Biology...) Apparently in the UK they all require you to declare it upfront. Whatever the policy is, the timing of the decision/determination doesn't change what it is, and again, even if it did, most schools let you if not require you to declare your major (what you call "degrees") in the beginning.