I rode my bike here yesterday. All the paths that are on OSM are still there in the field. Generally more overgrown than I've ever seen them though.
Specifically at the location of the pin, `smoothness=very_horrible` is quite accurate. Only for experienced mtb'ers or people on foot with wellies. As Ward somewhat suggests, I think it is indeed on purpose/policy that they try to keep the water table as high as possible here. I propose I'll update some of the landcover according to latest imagery and put the smoothness tag on this specific stretch.