That report, despite being lokal nooz, is pretty accurate. The school head is the authoritarian A type Kim identifies. Some time in the 2018-19 academic year, the school instituted a rule forbidding kids going into those shops, which are a few hundred metres from the school. This was due to junk food concerns coupled with the normal petty theft (or pathetic attempts at). The shops themselves have had "no more than 2 school children at a time" notices since forever, not that they're enforced. From autumn term 2019, the school put staff on the crossing and outside those shops. Kids stopped going to the shops (which include a Chinese takeaway, Chilli Bellies), traders lost a lot of revenue and asked the school to let the kids back in. School refused. When the school stationed staff in hi-viz outside the door of one shop, preventing even adults entering it, the shopkeeper called the police, who moved the staff on. The owner of Chilli Bellies has threatened to sue the school for loss of income, which I believe he estimated at £30 a day, though I don't know if he's carried that out.
Edit: Most of the problem is lack of communication, as it so often is. The school didn't talk to or even tell the shopkeepers about their scheme, just stationed the "bouncers" there.