It’s 3 across the sub category, some stores are obviously interpreting it incorrectly. So 3 each fresh milk, cheese, yogurt etc. 3 across fizzy drinks not 3 diet and 3 regular but 3 total across that sub category, 3 across cat food, 3 biscuits, 3 bread items. Wine is 3 red and 3 white so you can buy 6 total. Bottled water is 3 total, whatever flavour you’re buying.
Things like toilet roll, pasta, rice, tissues, uht milk, kitchen roll, anti bac products are limited to two max. Anti bac is sprays and wipes so only one of each if you’re getting both. Wet wipes but not baby wipes count as tissues so one pack of tissues and one pack of wet wipes is the limit. Pasta is two packs for the category not two of each type so if you want spaghetti and lasagne sheets it’ll be one of each.
I get it’s hard to follow because it’s all been set up based on the sub categories they fall under on the system and it doesn’t always make sense but to say you’re unaware of the rule at all is rubbish.
I would query someone who was saying three dairy items total because that is wrong and obviously not workable for any household.