At least if Le Pen wins the EU will collapse and at least the UK will be able to talk trade deals with who ever we want to in Europe.
So that would leave the UK with 27 trade deals to work out. Further UK companies would have to choose which countries they wish to trade with as we’d no longer have EU (CE) standards.
With BREXIT it will just be ordinary people in the UK that get poorer, if the EU falls apart ordinary folks right across Europe will be worse off.
But as it is we don’t need to talk trade deals with anybody in Europe as we are currently still fully paid up EU members. The UK has not yet left the EU and may yet still come to it’s senses.
Meanwhile the reality is that Macron will win the presidential election – but will he be able to form a government?