Even if the covenant to which you refer is on your neighbour's Register it is of no direct use to you. You cannot enforce it. It is an undertaking between the developer and the purchaser only, not between adjacent purchasers. If your estate is not sold out then you can point out the breach to the developer in the hope that they will enforce it to keep the estate tidy until it is sold out, but after it is sold out the developer will not be interested in any way whatsoever. You can contact your Planning Department to enquire whether this was a condition by them applicable to the whole development, and, if so, whether the Enforcement Officer will take it on. If not, and the chance of a yes is very slender, then the only other remedy is Nuisance. Noise, blocking light, movement, people living in it, danger through concealment, danger through gas being stored in it, interference with rainwater disposal, loss of enjoyment of your own property plus 50 other things you can think of yourself all constitute legal nuisance. The Enforcement Officer may take an interest in this type of nuisance, if not then you are left only with appearing before your local court through a solicitor and counsel to plead for relief by an injunction to cease the nuisance.