Obviously I am more than aware that certain subjects are needed for certain degrees – I said as much in my post actually.
Yes you are well advised to take maths and physics A level if you want to study engineering; if English lit is your degree choice, then you'll need that at A level. And so on. Tho interestingly it's more than possible to study history or geography, both on the Fac Subj list, without taking them at A level.
I never said the choice of A level subjects doesn't matter. Of course it does and DC would be well advised to consider it. How often have we all seen threads on "my DC wants to study engineering but didn't take physics/maths at a top uni and didn't take FM" or similar.
But BUT a pp said students are recommended to take at least (!) two Fac Subj – I would say that is good advice if they really don't know what they want to do and there are subjects on that list they really enjoy; but if they know they want to take art, psychology and DT, and they realise that that means they are closing a good number of doors (all A level choices close doors, but those choices would close more doors than, for example, Eng lit, French and German, or Maths, biology and chemistry), then I don't see an issue. It's not a problem choosing A levels that won't let you be an engineer, or a doctor, or an Eng lit graduate, if you have no interest in any of those things anyway. Better by far to take three subjects you enjoy and will do well in than to force yourself into a rigid list of subjects that are not your bag.
(and I speak as someone who took three fac subjs at A level and whose DC took respectively three and two!)
Edited to add: of course it's the case that the OP is talking about GCSEs so it's what Joey would call a moo point for this matter; but all kinds of people may read a thread so a wider discussion may help them.