I need some advice/ space to vent we have decided to extend our 1930's semi we live in NW London and can't afford to buy larger property nearby we have boy/ girl twins who currently share 2nd bedroom as third is teeny, have planning permission for loft and L shaped extension, it's probably going to cost over 100,000 pounds now the neighbour is being difficult about party wall agreement and trying to get other neighbours onside, they have one grown up son and have a small rare extension which we didn't object to, she's still being friendly and her husband is talking to my other half but it got a bit heated yesterday starting to feel really stressed, can she put a spanner in works?