For anyone cycling from Dunkirk to Calais on the EV4, a new autoroute has been built over the top of it! We struggled to find a way round and ended up on a busy N road (thankfully not for very long but still not idea with big lorries). There were no signs to show us a diversion but I have just googled it and found this - https://www.lavelomaritime.com/cycle-route/gravelines-dunkerque. Sharing in case anyone else planning a route is going that way (google maps doesn't even seem to know about the issue). 

P.S. Thanks cycle.travel you are the best site and have helped us plan so many excellent routes in UK and Europe!