The sellers form relates to disputes that are associated solely with your property. The vendor is not required to enter disputes with the owners of other properties. Even then the disputes break down into two, the trivial, ie your child threw a ball into my garden last Wednesday, and the important, ie your fence is three feet inside my property.
With regard to anything other than your right of way, my advice, based upon my understanding of what you have written so far, is to keep your dispute simple in case you have to go legal. It is far, far, better to go to court with one straightforward point which you have a 99% chance of winning rather than a dozen slightly fudgy ones of which you could lose six or eight.
The target is to establish the maximum exact area over which you have a right of way, to consider whether the bollards can be turned to advantage, and to obtain the maximum area of right of way outside your garage for you to manoeuvre in. I look forward to learning the exact wording.