I totally agree with you about illegal dumping of waste - no different from fly tipping really.
What I should like to get away from, though, is the notion of "wild camping" where use of vehicles is concerned. As far as I know, the only area of the UK where wild camping is allowed is Scotland and the definition enshrined by law there specifically excludes use of the majority of vehicles - see
Here.
In the rest of the UK, camping other than on recognised sites is only legal with the permission (or at least the tolerance) of the landowner. However, where vehicles are used it should not be termed "wild".
I worked for local authorities for nearly 36 years so I am well aware that councils will listen to approaches they receive regarding facilities (of all types) - but only if the approaches are constructive. This applies to both general and overnight parking for motorhomes as much as to anything else.
Graham