Thanks for your reply.
If a person uses land which does not legally belong to them for parking, they acquire a legal right to continue to park there IF they have done so for a continuous period of 20 years or more, WITHOUT permission of the true owner.
Therefore, I am afraid to say that as the previous neighbour granted you consent to park on the land, your "20 year period" did not start to run until the previous neighbour sold to the current neighbour.
I note that the current owner has only been living there for 10 years, and as he has recently requested you to stop parking there, you have not acquired any legal rights to continue to park on the land, because you have been using it with consent for a large proportion of time.
I realise this may sound ridiculous to you but you would be in a far better position had the previous neighbour not granted you any permission to park there!
Your current neighbour is therefore legally entitled to ask you to stop parking there.
As regards him blocking the access, this is a clear breach of your right of way. If it continues, you should consider sending him a Solicitor's letter demanding that he stops tobstructing the right of way immediately and forever thereafter, or you will have no alternative but to take him to Court with a view to obtaining an Injunction against him. Although I am sure you would not want to take such proceedings, the mere threat of it will hopefully make him see sense.
I am sorry this is not the answer you were looking for, but it sets out the legal position.