We built a single story extension to our detached house, in 2015.
The day we put the house on the market a year later our neighbour complained to the council planning department about the extension.
It included a number of points, one of which claimed it was structurally unsound 
Immediately we got a structural engineer around to reassure them that the minor cracks were just that.
However one issue remains unresolved.
The gutter does slightly overhang into their airspace.
They were happy during the build, everything was explained to the , we shared the plans and hid nothing.
We have now moved, a letter from a solicitor dropped through our door yesterday, threatening legal action unless we pay them several thousand pound for the inconvenience of the overhang.
Any advice would be gratefully received