Means nothing really. Just because a GP mentions it on a morning TV show doesn't mean our lot won't do it, though I admit that it's unlikely to happen just because of how stupid it is (though in saying that, this is a government that dictated to its own people what is and isn't essential and banned them from buying anything they deemed non essential).
If they somehow do go ahead with this, it will pass as they have the nationalists on board to basically pass through anything.
I've already said before that the restriction of energy drinks is a good thing. However, as per the same article:
'Banning the sale of tea and coffee to under-16s in Wales is something being considered as part of plans to make young people healthier and stop rising obesity rates'.
The part in bold is important because, as I mentioned previously, if we're banning tea and coffee (which you yourself have highlighted that 'there's no real evidence for long term damage from caffeine in tea and coffee'), why has the banning of fizzy drinks not been considered (which has been proven to cause damage due to the high level of sugar), but they're considering a tea and coffee ban instead?
Who knows, maybe they have considered it for fizzy drinks and you may very well be right that the headline is purely focusing on that just to piss people off. However, I'll say that if Boris did the same, he'd be rightly ridiculed.