In the UK ‘Sudafed’ (the brand of decongestants) is available off the shelf, but doesn’t contain pseudoephedrine. There is a different ‘Sudafed’ branded coloured box that you can get from behind the counter by asking someone, that does contain pseudoephedrine.
I find it funny that “things you need to cook meth” are such common knowledge among normal people.
Breaking Bad sure had a deep influence!
It's more due to the fact that you can only buy it in tiny amounts "because some people use it to make meth." As far as I know, that restriction predated the show by several years at least.