OK, so the UK is no longer a member of the EU. Then what?
You've got that backwards. It is the EU that will not be part of the UK then.
I remember an old joke told by my mom - newspaper headline:
"FOG IN THE CHANNEL - CONTINENT ISOLATED"
I think the UK will get a deal like Norway after some fierce bargaining. Which means no influence on the rules governing the EU market and politics, but able to sell to and buy from it without too much hassle. If the UK don't upset the old EU too much, that is.
Reading around a bit I see they (UKIP) don't really have a clue what the heck they are doing except wanting to guarantee everyone the freedom to starve to death as long as no money will be harmed. Like Liberal Alliance in Denmark. Which I utterly despise for their right-wing populist "libertarian" rhetoric while they spit hatred against everyone less fortunate.