That's not strictly true .. a negative (restrictive) covenant usually passes in title to the next owner if the property is sold or annexed. Covenants can also be enforced by interested parties - even if they don't own the property upon which the covenant is burdened. For instance, you live alongside the same road as a property that is covered by a covenant restricting business.. Whilst you may not have title to the covenant, if the operation of a business had a measurable impact on you .. and it would normally require a measurable loss or a trespass - then you could seek to enforce the covenant even if the owner of the property with the covenant in the title did not.
Complicated and very ancient law - but it's there for people to protect their reasonable rights and the courts will always uphold what are considered to be reasonable rights.
As you point out .. parking in the lane may also be an infringement of the covenant in the OP's case and would be considered trespass in the eyes of the law.
Not my area of expertise, I had partners/staff to deal with boring things, though I did pass exams in land law and conveyancing way back when dinosaurs roamed the land. Nobody ever offered to pay me to take on a dispute over restrictive covenants, but as I recall, most covenants are expressed to bind the purchaser and his successors in title. It's who can enforce a covenant that's more difficult.
Twenty years ago I was acting pro bono for a community association (well, I lived and worked in that community, so it was self-interest that encouraged my generosity) trying to stop an old tram-shed from being turned into a pub by a brewery. There was a covenant imposed banning the sale of alcohol on the land when it was sold by the Brudenell family (Lord Cardigan's lot) for development. My conveyancing colleague was of the opinion that we might have a chance of enforcing the covenant if we could get the descendants of the family to object, but the neighbours would have no chance.
We saw them off by defeating their application for a liquor license. The vicar, the MP and councillors from both the Labour and the Conservative party all turned up to give evidence, and the following week the Lib Dems, invisible and silent at the hearing, if they were there, claimed credit in their newsletter.
Parking in the lane would not be considered a proper use of the right of way, and the neighbour would almost certainly be granted an injunction preventing it. As to its use by customers on foot, if there were a constant stream, it may be considered an abuse of the right. A few a day may not be unreasonable. The right of way is something wholly separate from the restrictive covenant.
I've been involved in a lot of neighbour disputes, both as a solicitor and as a mediator. Save where one party has psychological problems, there's usually something that caused the problem to kick off in the first place, something unrelated to the matter being argued over, but which has caused bad blood between the parties. The OP reminds me of so many that I've seen in these cases, unwilling to give ground and accusing the other of being unreasonable.
