Mind that sandwich

Some products are not subject to VAT in Europe; others are. With VAT in the UK at 17.5% and going to 20.0% whether it is taxed or not makes a big difference. So, is a toasted sandwich from Subway just that and not subject to VAT or is it hot takeaway food when, apparently, it is subject to VAT? In a related dispute, a sandwich eaten sitting down inside the door is subject to VAT, but one eaten standing up just outside the door is not. Go figure!