I would liken it similar to that as starting up a business again, almost from scratch, and every hospitality business/business area within the UK will be in a similar situation. I don't see that as being wrecking the economics of the operation; doing nothing and not attempting to adapt would do that. Far more labour intensive an operation it may be, a short term possible lesser food selection (drinks I can't see being much different if I'm honest apart from perhaps the cocktail aspect) but if they don't do this, there is no operation available full stop. I can't imagine anything to be perfect from the off, it will no doubt be very very different, but to be frank so is almost everything else in the UK from buying a loaf of bread, seeing a doctor,or catching a bus/train for example.