Unless there are relevant covenants in place, restricting or barring the erection of fences, he's fully entitled to erect such a fence.
Even if your neighbour has breached a covenant, only the person (or body) who originally obtained the covenant can seek to enforce it. That would normally be the property developer; most developers seek covenants in order to keep local planners happy but, once the development has been completed, they cease to be interested in actually enforcing them.