Right of access over neighbours drive

[mjc23]

Hi all,
I'm hoping for some help with regards to our neighbour's driveway. We built our house a few years ago on the land we purchased from the neighbour in question. They retained ownership of the 40 metre driveway but we have legal right of access over it to our house and have to share maintenance and renewal costs, which is fine.
The owner has now rerouted the drive which has created a very tight right angle which only just allows enough room for our cars to get up. Unfortunately we can no longer get our caravan in and out and vans can't get up either. The neighbour sometimes opens the top part of the drive up which was the original route which allows us to get our van out but often it's blocked with garden or building materials.
I appreciate it's not our land but I feel the access is sub par and definitely worse than the original plan. Are we within our right to enforce the original access remains or at least an acceptable amendment to the rerouted access which allows enough room for our caravan, vans and emergency vehicles to use?
Any help would be greatly appreciated.

[des8]

a certain amount will depend on the wording of the agreement that gives you the right to travel over his land.
If it was delineated your neighbour probably cannot vary the route without your express agreement.