Supermarkets can set their own rules for selling things, as long as they themselves follow the law. In effect they are inviting you into their premises to buy their goods, under their rules. Of course, if this is disagreeable to the customer, they have numerous other places they can go to buy their shopping, so the rules are not so ridiculous as to drive customers away.
Challenge 25 is a rule that most supermarkets these days follow. It is designed to provide a buffer zone between the legal age, 18, and the huge differences in
apparent age of customers, so that a checkout server can be challenged in the event of a deliberate serving of a minor. You'd be surprised how difficult this is at times.
You can get round this if you fall into the uncertain zone by carrying ID, what's the problem?
I do however think that some people can be over-zealous with the rules, and asking a 50-year-old man is just ridiculous. I also think that refusing a sale when someone is with an under-age person is making a judgement too far
But then, as far as I know, you can be prosecuted for selling age-related products to someone if you have a reason to think that they will give it to a minor, I think a local shop got done for this the other day, but I might be mistaken
