I dont believe that there are any car park issues there now.
I dont know why the gate has been removed and the post holes concreted.
The ROW access point at the tarmac road needs to be confirmed by the local authority and signposted.
I dont even know that the landowner there is part of any equation
As a point of interest, and this does not point a finger at anyone, its here for reference purposes.
Highways Act 1980
Section 137 – Penalty for willful obstruction.
(1)If a person, without lawful authority or excuse, in any way willfully obstructs the free passage along a highway he is guilty of an offence and liable to a fine not exceeding level 3 on the standard scale.
A highway is defined in English common law by a number of similarly-worded definitions such as "a way over which all members of the public have the right to pass and repass without hindrance"[1] usually accompanied by "at all times"; ownership of the ground is for most purposes irrelevant thus the term encompasses all such ways from the widest trunk roads in public ownership to the narrowest footpath providing unlimited pedestrian access over private land.
Responsibility for Motorways and trunk roads lies with the Highways Agency, who also usually own the land over which the highway passes. All other roads are local authority.
My avatar is a poor likeness.