Re: Can't see banking being retained but goods not.
Turkey is part of the customs union, this means no duties between Turkey and the EU on goods.
Yes, but duties are now considered one of the smallest barriers to trade which is why we hear so much about "non-tariff barriers to trade"
Norway is part of the single market but not part of the customs union (hint this is a bigger deal and much harder to get). There currently seems to be a lot of woolly and wishful thinking about the kind of the deal the UK can expect from the EU. To be clear, Article 50 was set up as a poison pill to make leaving the union as unpalatable as possible. It hands all the cards to the other member states and negotiations are done by the vast army of skilled trade negotiators that the European Commission has at its disposal.
Unless the UK signs up to the single market then passporting for financial services is almost certain to b lost. Although it's extremely capital intensive, it's also much easier to move the offices and workers from London to Dublin, Amsterdam, Paris and Frankfurt than it is to move factories from Sunderland and Derby to Wcoclaw or Bratislava. If passporting goes then the City will almost certainly lose other business such as the nascent Yuan market to Hong Kong or Singapore.
EEA membership is unlikely (Norway has indicated that it would veto it) and couldn't be split for Scotland and Northern Ireland. But we won't really know more before Article 50 is actually invoked.