As mentioned it is a best before date, but I was told they are allowed to sell things upto 1 month past the best before date (had this said in B&M to). Though its common to see things in my local poundstretcher 3 months past best before. They never seen to pay attention to their stock
they can sell things that are past their best before but not use by
Not an offence to sell after "best before", but is to sell after "use by". Bottles of fizzy juice are generally BBE and not use by.
I didn't think shops were allowed to sell out of date goods, ho hum, you live and learn.