Bear in mind that most Routiers are shut Saturday and Sunday , if you do get stuck in ban , I would park up at the motorway services , their quality of food is excellent compared to the muck they dish out at any UK MSA , everything is fried or with chips .
If you show the till operator that you are a hgv driver , you get a percentage off your meal .
I have never been asked , just say chauffeur poids lourds or camion should suffice .
Failing that , find a place near a village, town or city and walk to a restaurant .