I'm delighted to hear that some of the shops will stay closed on Boxing Day. Everyone needs a break, whether that be from working or from shopping.
I live in the countryside and we are always geared up for bad weather in the winter. If we need to we can manage for a couple of weeks without a shop. We have a sack of potatoes from the farm shop at this time of year, some UHT milk for emergencies, tins and packets and jars of stuff, the cupboards are full. What can anyone possible need form a store on Boxing Day?