DMcG,
A few organisations reporting Brexit concerns in the past couple of days:

Of course they do. There is uncertainty about what the deal will be. That is all they are concerned about.

They are concerned whether there will be a deal at all. Whatever is or not decided they are concerned how that affects their financial plans as reported to shareholders. They are worried the shareholders might not think they are taking the right decisions. They are concerned whether it is better as a company or not to relocate. They are worried about the risks of taking the wrong decision. They are worried that the wider ramifications like possible delays at ports might require them to change JIT processes that are key to how their business runs and to invest heavily in warehousing with its concomitant costs. And on and on.

And you say that is 'all they are worried about'. I put it to you that is quite a lot.