i read a surprising stat recently, i dont recall the exact number nor do i necessarily believe its the full story, that something like 95% of business transaction in the UK are within the UK. it seemed fantastical, but if you consider every shop, builder, accountant, garage, resturant, small factories, distributors, you realise thats probably not wrong. yet all those businesses have to comply with all EU legislation in order to maintain the premise of a single market. apart from Amazon (based in Luxemburg to benefit from lower tax) I dont think i have ever made a purchase from a EU nation. so that "potential customers" line is very possibly a little distortion of reality.
Not at all.
I work for a company which sources around 35% of its products directly from Asia, another 50% from Europe (although the original source is often Asia, and another 15% from the UK (originally split 50/50 from UK and other sources). We import from Europe when needed due to the economics of volume, one European importer can get far better prices than 15 different companies all trying to negotiate in the far East. If the free trade area were to cease our buying prices would increase thus leading to higher retail prices.
And the free trade zone WOULD cease if we leave the EU, it is a club that demands a membership fee in return for priviledges, no fee equals no benefits.