Thanks for your reply.
If no access was granted by your father when he sold the land, and there was not already a right of way granted to the land by the previous owner of the road, then the owner of the land does not have any legal right of way.
There is a proviso however- if the past and current owners of the land have been using the road, without dispute, for 20 years or more, the land acquires what is called "a prescriptive right of way", meaning in simple terms that the land has an established legal right to use and continue to use the road. This right is created automatically after 20 years usage, and it is not even necessary for the owner of the land to notify you of this acquired right.
I am not sure how long ago your Father sold the land, but if the land has been using the road to gain access to the land for 20 years or more, the
new owner does indeed have a legal right to carry on using the road for access purposes.
If the land has not had the benefit of using the road for 20 years, then the new owner has no legal right to use your road, and you are within your rights to stop him from using it. Alternatively, for a cash sum, you could consider granting him a formal right of way.
I hope this assists and sets out the legal position.