First view of the text - there is awful lot buried in a list of EU regulations that Northern Ireland will have to follow under the deal. Second, most of the detail on future GB-NI-EU relationship is put into the next stage
Northern Ireland in effect part of the EU Customs territory through this provision - and while the UK can negotiate trade agreements covering Northern Ireland, this will be a complication. Also not clear to me yet if Northern Ireland input eligible for EU trade agreements 
Now to try to sum up for @britishchambers trade conference...
