Is My Neighbour’s New Garage Covered by the Party Wall Act?

Question

My next door neighbour door but one is building a garage which comes into contact with my boundary for about 600mm at the very corner (rear) of my back garden, during construction he or his builders have interfered with my fence line which has now left a gap in the fence.  I told him under CDM regs that he had not notified me that he planned to start any works, is this CDM or Party Wall regs?
 
He also claims that it was actually the neighbour behind me who removed ivy from on top of his garage and that caused the gap, I am certain that it was a fence panel there covered in ivy anyway but I want to challenge him on that.
 
Have I any  grounds under Party Wall?

Answer 

If your neighbour’s new wall is built up to the boundary with your property then he should have served notice under Section 1 of the Party Wall Act before starting. If it is back from the boundary by even a few inches the Act doesn’t apply.