Don’t take everything at face value: a fall in Sterling necessarily means that an exporters products are cheaper overseas, so should boost sales. Unless their costs were already higher than their revenues, in which case they were doomed anyway. The reason brexit will be bad for exporters is the possible future imposition of tariffs. This hasn’t happened yet, so actually in the short term brexit is relatively good for them. Just to be clear I’m against brexit, however in this case blaming brexit for the failure is wrong.