Stories in the financial times indicated EU leadership would take a harsh line with Britain as a warning to other member states. This could perhaps include punitive tariffs on British built goods (cycles) imported into the EU.
I would also speculate that Brompton would lose standing in EU courts for their copyright infringement claim.
The EU is Brompton's largest export market, and the company might be facing a Euro future of selling a more expensive product in competition with floods of Neo, MIT & etc bikes.