Read it again as it 25% of EU trade to Britain not 25% of total trade.
This is a link to the British section:
The World Factbook
Choose “Economy”; scroll down and you will see “Exports - partners”, here you can see seven countries: US 14.6%, Germany 10.1%, Switzerland 7%, China 6%, France 5.9%, Netherlands 5.8%, Ireland 5.5% (2015). Where does it say about ‘it 25% of EU trade to Britain not 25% of total trade’?
Then they will find themselves in court and being forced to honour contracts they signed. Then they will be forced to pay huge sums in compensation, possibly making them go into liquidation in the process. They will also be blacklisted for breach of contract putting the cost's up in the future
Actually, it is your British firms may find themselves in courts because they will no longer be able to fulfil their obligations due to limited access to the EU market.
If the bussines model used by the firm is theirs then the model can not be used by another firm without their permision, so the company would have to hunt for another one that is freely available and works for them. The access to Europe will still be there as Europe wont want to lose that much of its banking because of pettyness.It is just the new contracts that will be at risk, and they can be made just as watertight
I still can’t understand what British firms can do such exceptional that say German or Irish ones can’t.