“I really do lament the idea that we wish to be so insular, so localised.”
I only just noticed your last line. What on earth makes you think the UK is (or will be ) “insular and localised”? One of the main objections many people have to the EU is that its Single Market and (particularly) its customs union prevent or severely hamper member nations from striking out across the world to do trade. Quite simply, EU legislation does not permit it. Every continent in the world bar Europe is experiencing growth, considerable in parts. EU nations are prevented from striking deals abroad and so cannot benefit from that growth. By the time the EU gets round to amending its legislation to facilitate trade, the ship has sailed. Few place on earth (with the possible exception of North Korea) puts up more in the way of barriers to normal trade the EU does. The Single Market, whilst not all it's cracked up to be, is not a bad idea. The problem is it's facilitators seem to be under the illusion that there is nowhere else in the world that people would wish to do business.
I wish you well when you leave this insular island and seek your fortune elsewhere. You may find (if you bother to investigate properly rather than rely on propaganda) that the grass is not quite so green as you would like to have us believe on the sunny uplands upon which you seem to think that the EU sits.