Remember – the argument is thus “Johnny foreigner, weak willed chap as he is, is so dependent on exporting his goods to the UK that we can thumb our noses at him, insult him, walk from his club, and he will still be nice to us. No gumption these foreigners.”
The lines show the 2014 $ exports to the Uk from the three main counties. The bars show the % of exports in that sector which go to the Uk. All data from the World Bank
With few exceptions – the areas where the continental countries are most, proportionally, exposed to the UK are small in monetary terms. The massive exposure of France in stone and glass is, in financial terms, a nothing. Cars and consumer goods are large in both money and % terms. But the others? not so much. TL:DR – Sorry England, Johnny Foreigner can get on without you – you really are not that important.