Firstly, I am fairly sure they can insist that you remove the post attached to their property. My friend had this issue with a neighbour when he wanted to attach fence posts and rails to his neighbours garage wall. The neighbour was not keen for whatever reason so my friend had to dig holes and secure the posts with concrete. His solicitor advised that his neighbour could insist on no fixings being drilled into or attached to his wall. Secondly a lot depends on your relationship with this neighbour. If it is friendly say you are prepared to remove the post and reposition it in a hole with concrete to secure it and allow a space between it and the wall. Ask him if the post or the gate operation is causing a nuisance. If so he is right to complain. If you accept this it should change their attitude. Thirdly keep well away from the legal remedy in this matter. It will be long, complicated, expensive and the outcome uncertain. What is certain is that would destroy any relationship you have with this neighbour. Good neighbours are like gold dust and you are fortunate if you have them. We do and are thankful for it. However even the slightest acquaintanceship still needs to be on good terms and these need to be fostered. Your neighbour may have gone about this the wrong way which has obviously disgruntled you, but you need to accept the situation for what it is and comply with his, albeit not very polite, request and move on. You will come out of this better than they, especially with the other neighbours. Show that you know how to behave with civility and are capable of doing the right thing to remedy matters. It may not seem important now but it really is. Good luck.

Cheers Concrete