Well jim, I think you're mixing up spending ages preparing for all eventualities with getting on with something and dealing with issues as they arrive. There will be an optimal balance between the two, which I suspect we've already surpassed. So yes, we could leave today, let along tomorrow. But until government opts to make progress towards leaving (rather than avoiding no-deal and adding extensions in the hope of parliament accepting May's /the EU's guano 'remainer deal') there will be avoidable issues one would run into.