Four years or forty years, two or two hundred people the situation is the same - freeholders cannot enforce this type of covenant against each other. It is a common problem with all types of covenant relating to washing, fencing, caravans, boats, vans and lorries, parking etc. There is always someone who comes to live there who will not voluntarily behave. Write to the developers tactfully and ask. If they turn you down then there is nothing you can do about that - the developers have no duty to you to enforce a covenant - but nothings lost by asking. The only other legal is an injunction, which would be successful if you were totaly blocked but is 50/50 if you can still get in however awkward.