The Single Market is like a customs union. Tax and duty paid in one member country is deemed as tax and duty paid in another member country and so goods are free to move across borders between members. Many readers eher will not remember the bad old days when trucks crossing borders had to queue and wait for a customs official to measure the amount of diesel in the fuel tank and then the driver had to pay tax on the import of that fuel into that particular country. Only passenger vehicles were exempt.
Hannah is simply playing word games. He admits the EU is internally a free trade area but, the fact that it is not free and open to the world is not unusual. Most of the world is not free and open to the EU or to many other parts of the world.
Hannah provides examples of free trade areas, Nafta (Canada, the United States and Mexico) and ASEAN (ten South East Asian states). The EU is setting up similar Free Trade Agreements, EU-Japan Free Trade Agreement, EU- Canada Comprehensive Economic and Trade Agreement, EU-US Transatlantic Economic Council, EU-India Free Trade Agreement, EU-Mercosur Free Trade Agreement.
Hannah says nothing but he does demonstrate his naivety; "The optimum deal for the United Kingdom is surely to be in a European free trade area but not in a customs union." That's like saying that the optimum deal for the United Kingdom is one where the UK is the sole winner.
We'd all like unlimted freedoms but with no attached responsibilities but you will never ever eliminate 'if you sell to him, I won't sell to you' and very quickly, 'and I'll ask my mate not to supply you at all'. Deals are struck, bargains are made. No one allows a single trader to take all the profit.