Newer estates all have Restrictive Covenenats that usually prohibit using your house for business, parkeing commercial vehicles etc. There is one on my own house.
I asked the solicitor about it, and he enquired of the builder. The builder (a big house building co) said no flexibility whatsoever. They are legally enforcable as they are written into the deeds and have nothing to do with the mortgage.
In practice however, from what I've seen these covenants are widely ignored! I always keep my van tucked away in the garage (which is still breaking the covenant actually) but I can see at least 4 or 5 vans on drives just on my estate.
The only time this will cause a problem is if you really take the mick (like parking a 16 wheeler outside or running a shop out of your garage etc) and then even reasonable neighbors will probably complain.
Or if, as you have seen, you just get a nightmare neighbor who is determined to cause trouble.
Problem is, they do have the law on their side, and you can be forced to comply with the covenant. If it happened to me, I would rent a commercial unit, but so far I have been lucky not have idiot neighbours.
I agree with what's been said, it's better to try to smooth things out with a neighbor, because you basically don't have a leg to stand on.