If it's possible to walk up Snowdon, it's possible to drive up it in a 4x4 (Even a Frontera although I'd be happier using my Range Rover...). How can anyone be charged with dangerous driving offences (as the BBC news story says) when it isn't public highway? There may be local byelaws that say you can't drive up it but that doesn't constitute a motoring offence, only an offence against a local byelaw.
Anyway, didn't Top Gear drive up Snowdon in a Discovery? OK, they probably got permission to do it but what's the difference?