I've heard similar stories about HDDs having different controllers, number of discs and so on.
Luckily in EU one can return within two weeks anything ordered online, so a simple solution is to order, test and return if it doesn't match expectations.
https://www.gov.uk/online-and-distance-selling-for-businesse...
You're better protected if you buy online than in a store, ironically.
PS: I looked it up, and actually the DSR has been superseded as of yesterday (!) by Consumer Contracts Regulations, which ups the UK protection from 7 days to 14 days, bringing it into line with EU directives.
It's the only thing that makes sense, particularly if you want to instil trust in customers that buying online is "safe" and not prone to scams.
In my experience, it's not particularly unusual for grocery stores to take back open food, even.
I have heard personally once, and online many times, from foreigners marvelling at how readily many US retailers will take returns, even for silly reasons.
I am not aware of any regulations mandating such practices, though I suppose they could exist.
Some just sort of unofficially try to keep customers happy, but some are up-front about it. Costco, for example, lets you return almost anything almost any time for any reason, or no reason. Electronics are limited to 90 days, but others have no limit. Bought some fruit that doesn't taste quite right, possibly because you left it in your car for two weeks? Just bring the moldy remains back. In the world of clothing, LL Bean and Lands' End are two examples where they take pretty much anything, any time. Lands' End even has an amusing story that they use to promote their crazy return policy, about a man who bought a collectible car from them as part of some promotion, and his widow returned it 20 years later after he died. (Two decades of inflation no doubt ate away at the true value of the refund, but still.) LL Bean will go out of their way to remind you of their policy. I had a button break on some pants and when I asked if I could get a replacement button somehow, they told me nope, just return them and we'll send you a new pair.