Hello and thank you for your question. I will be very pleased to assist you. I'm a practicing lawyer in England with over 10 years experience.
from what you say, do I understand correctly that you accept that the fence in question which he is replacing belongs to him as opposed to being your property please?
You understand correctly.
thank you. A neighbour placing the "good side" of a fence facing away from his property towards his neighbour is unfortunately nothing more than a polite social convention. it is unfortunately not a legally enforceable convention
it is quite possible for you to correct your own fence or boundary structure on your side of the boundary to hide his fence posts but obviously this would incur costs on your part and says unlikely to be an attractive proposition
*correct = erect.
Apologies for the typo