Would Steve Odell change his mind if, at the same time that Britain left the EU, it adopted unilateral free trade? I don’t see why he would not (change his mind, that is). If he wants to meet the EU regulations in order to export there, nothing would stop him. He would be in the same position as if Britain were still a member. But unilateral free trade would liberate from costly and burdensome EU regulations those British companies that do NOT want to export to the EU. Local companies with only British customers, such as many small farmers, could ignore EU regulations altogether. The same logic would apply to those who exported to non-EU countries.
There’s a bigger world than the EU out there for British goods.