Those plastic bollards have gone,

From my understanding there is a "right of access" to belle view through the Super Bowl car park, not a "right of way" this means that whoever owns the super bowl land at this time has to allow access to the ground over it. It's easier to remove a "right of access" than a "public right of way" all that said I could be mistaken

I think you are mistaken. It wouldn't be easy to remove that access at all.

They can't just block right of access everyone's getting paranoid

We have access to the ground from the Donny road turnstiles, they could quite feasibly erect fences to protect people from injury by erecting fences on the perimeter of their building plot.

I suppose for a sports stadium, there are two types of access. One is pedestrian, which can be accommodated with a ginnel. The other is vehicular, for team coaches, etc. That needs a lot more. If Belle Vue remains a rugby ground, I'm sure these things become part of the planning process. If it doesn't, it makes no difference either way, and you could build a pretty big estate on all that land, and with access onto Doncaster Road only, it could become decent real estate and distinct from Agbrigg.