john west++++ wrote:
Hi, my neighbour and I are going to build a new wooden fence. At one
point it has to go between a very narrow walking space between our
two houses particularly at a place where every inch counts.

Are you trying to restrain dogs, children, etc. or merely mark the boundary?
It's not uncommon in instances like this to keep the actual bit between the
houses open. You can pave it, and mark the boundary line with contrasting
bricks, slabs, or even stainless studs with colourded disks around them.
That way you get good, safe, access to both properties for maintainence
without setting any precidents.