The problem with those legal rights is that they are based in a time where off-roading didn't even exist. These were historic routes which were actually used for basic movement of essential goods and - well, anything, really. They fell into disuse with the successive arrivals of canals, railways, then metalled roads. There has never been, as far as I know, a specific right for off-roaders. What is actually needed is a change in the law or regulations, nationally, so that National Parks cannot make up their own minds about this. As it stands, they really have no choice but to bow down to the powerful lobby. We are not talking about the odd quaint little green lane; Mastiles Lane in the Dales, was a colossal thoroughfare from East Yorkshire over to Malham and beyond. Not too long ago it was easily rideable on a bike. I'm pretty sure it isn't now, except possibly in a drought year.
Peter
PS I didn't watch more than a couple of minutes; it was obvious what the result would be and it's just too distressing.