Advice on moving property boundary

[Red Herring]

If you are going to claim that the wall is built 40cm onto your land then it looks as if the porch has also been built on it. Is this not something you discussed when you saw where they were going to put the porch?

[sniff]

the porch I've no issue with. As i agreed this. Not stopping me getting into and out of my house. Its the wall that I have issues with. Its on the footpath that had a fence along it. You can see this in the on the google maps part. As far as I was aware this was my property as when I bought it and from my neighbour who has lived there since 1978 its was always like this. New neighbour lived there around a year were told they must put the brick wall back to the original fence line.

[Red Herring]

You may not have an issue with the porch but it could well cause you problems when you go to sell your property unless you formalize what has gone on. To a lay person, me for example, then I would assume in the absence of documentation to the contrary that the boundary between the two properties lies along the internal party wall in a line that continues beyond the building, ie: (if I have understood your OP correctly) where they have built the porch to and from there the wall.

If you want the external boundary to be along a different line, for example where you had the fence originally, then I think you will need to make a case for that to happen. If your neighbour is prepared to agree to that then fine, but get it documented for future reference. If he won't agree and maintains that the wall is correctly placed then my suggestion is that you explore the possibility of making a claim on the disputed 40cm of land by arguing that it has been fenced into your property for in excess of 12 years and you have had uncontested use of it as such.