Whatever your viewpoint, I think this is an informative read. It explains that establishing regulators for a country leaving the EU is a big deal and hard to do/impossible in the timescale of 12 months that Article 50 provides. 
	Quote:
	
	
		| Once you’re in the EU, you share regulatory infrastructure. You’ve entered into a regulatory web designed to make things easier to trade and run around the continent. Drugs are licensed by the European Medicines Agency. Intellectual property rights for new plant varieties are granted through the Community Plant Variety Office. The safety checks for airplane parts are recognised by the European Aviation Safety Agency. The legal oversight for the transportation of nuclear materials is provided by Euratom. If you leave Europe without a deal in March 2019, you lose access to these regulators. The consequences are sci-fi level bad. They are basically just not conscionable. No government with even a bat-squeak of responsibility would allow such a thing to pass.
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 https://www.prospectmagazine.co.uk/p...-europes-bluff
To me, the best way of leaving would sort out your plan, get as much inftrastructure in place as you can and then Invoke Article 50 from a stronger position.