The above is correct without your neighbour seeking Planning Permission for the fence. However, depending where you live, there may be another restriction. Most modern estate type developments since the 1960s have had a constraint put the erection of fences at the front in order to maintain the open-plan appearance of the development. This is not a Planning issue - the restriction will be in each and every owners' title deeds and is a legal constraint. Its the same sort of restriction that generally stops each estates having caravans parked, keeping chickens and goats etc. Have a look in your title deeds to see if it exists. If it does, enforcing it is another matter since it is civil matter, not a criminal one.