They've demolished the property next door which had its wall as the boundary between our garden and them. Today they've started work on putting two houses up which will have their wall on the boundary. They've dug a trench for the foundations and it straddles the boundary, how far can they come over and suppose we want to build ourselves later. Shouldn't they have served us notice for work on the boundary as party wall act? I'm feeling really stressed, can't speak to them because I don't know who the developers are and I'm at work.