>>We exactly the same experience in France walking by the Canal du Midi where a constant stream of cyclists coming up behind us at speed made it very unpleasant..

LOL. Happy memories of walking and cycling along the "Hydroélectrique du Rhin" canals with nobody else around and even encouraging daughters to invade France from Germany across the Rhine when the water is deviated to the canals over Summer. Quite freaky imagining French troops waiting for the Hun to attack. You only need to walk a few feet into the forest on the French side to find disused WWII pillboxes and tank hides. Highly recommended if you want a great tour without swarms of tourists.