I live on a plot where 2 houses reside with a shared drive I live in the property that was first built and I need to cross his drive to get to my entrance the person next door is aggrevated that his drive is used too much with domestic traffic going past his property always leave him with access at all time , now he wants to repostion the drive in his favour and put restrictive bollards down the middle of the drive so we cannot reverse on to his property , the new drive Will be very close say 20 feet[max ] from a corner of a busy A-road , if he builds the drive we will have to drive into the house and reverse out on to a blind corner of the road , the road we live on is private ,owned by the crown but the residence pay for any repair and up keep of the road , also the builder have a signed covenant from both properties agreeing to the shared drive when it was purchased 8 years ago for which I have right of way.
Can the next door build a new drive with our permission and inforce this on us YOUR FEED BACK PLEASE

As you describe it, this is an easement, and no one has rights over the other. Neither party should be leaving vehicles anywhere on the shared area. The lines of demarcation should be on file with your deed at city/town hall (although I am speaking about the US, which I doubt you are in). You should not be backing outside of it, and he cannot alter it or place obstructions down the middle of it. Of course I mean 'may not;' he is able, and you have to stop him in court. You might get good advice from a clerk at the deeds office, since they often have a lot of experience with this.
If he wants to build a drive on his property, right next to it, with a barrier, that's between him and town zoning.

... the road we live on is private ,owned by the crown but the residence pay for any repair and up keep of the road ...

This is in Canada?
It's private but owned by the Crown? How can that be?

A drive to get onto your property is one thing, a area to back into and turn around is another.

Could you not install a larger parking area or turn around on your own property after you drive onto your property