Please see this Toolkit distributed by NE-LEP:
WHAT IS THE BREXIT TOOLKIT?
This Brexit tookit will enable you to self-audit your current trade with EU countries to find out how much duty you will likely be payable on the commodities you import & export After Brexit.
You can also use the audit to find out if your business is ready to cope with post-Brexit customs regulation changes and in a position to take advantage of any relevant tax & duty relief schemes. If you need more help you can arrange an on-site consultation with one of our Brexit specialists, make a post in the Brexit forum or read through our Brexit international trade blog.