Yes, the results of such drastic actions effects are usually ambiguous in the short term. The simplest model involves taxes, property rights(regulations), wealth holdings (M0,M1,,,), labor(regulations), and net export(regulations) as exogenous variables. The EU has an advantage in all but wealth holdings. I'm an economist I only know utility as a person's greed; so I am not going to speak about utility from an emotion view. It will take weeks for the accountants to separate non-foreign taxed Pound transactions from Euro (and other non-monetary M0 confederate nations) holdings. The EU is not making any drastic regulation change. They are switching the UK's status from member to non-member which will have a large upfront tax payment to keep business as usual ( existing contracts have to be fulfilled). Meanwhile commonwealth companies can start bidding on British produced intermediate goods, because the changes means Germany might reject further contracts because the UK's status change. Ford North America might want Mercedes grade manifolds at existing prices... I am more concerned with the property rights British Kingdom or European Kingdom sailors which might be denied the right to enter a EU port with a commercial load...Think about the humanity as vacationers start planning a Brittany, France - to Denmark free cruise, because the British Isles started charging a EU exiting cruise ships an entry port fee.