Hello and thanks for using Just Answer.
I am Al and am happy to assist you with your enquiry.
Legally, you could take him to Court for breaching the covenant, but you won't want to be spending thousands of pounds doing this.
Therefore, on a practical basis, and on the basis that you don't want to create a neighbour dispute, I can only suggest you do a polite letter explaining that he is in breach of his covenant not to park on the driveway and that his actions are causing you inconvenience.
I will leave it to you whether you also add that you have taken legal advice and if he does not stop parking on the driveway, you will have no alternative but to issue Court proceedings and request the Court to make him liable for your costs.
Sadly, with these type of issues, there is no easy and cheap legal solution, and you will need to try and resolve matters amicably.
I hope this assists and sets out the legal position.