I have no idea how things are being implemented in England. BUT! In Wales, supermarkets were/are not allowed to sell non-essential goods. Two reasons: So they did not have an advantage over other shops, and to keep shop visiting at the lowest level consistent with getting essentials. Ensuring that there aren't many shoppers spending extra time choosing clothes, shades of paint, etc.
But paint has continued to be sold.
France seems to be going in broadly the same direction as Wales.