There is only one Honda plant in the EU. Also because of the new trade deal between the EU and Japan it’s possible cheaper for them to export from Japan than a UK because of the brexit (regardless if there is a deal)
That's not correct; there is an auto parts factory in Belgium and a light-machinery plant in France ( my lawnmower and generator hail from there ).
They are also planning to close the Civic production factory in non-EU Turkey which produced the saloon to import to the EU, to complement Swindon's hatchback.