We have exchanged on a property and are due to complete next week. Our new neighbours have just contacted us to discuss a party wall agreement for their new extension which planning permission was submitted around 3 weeks before exchange. We have confirmation in writing from the new neighbours that the vendors were aware of this "for quite some time". The extension is quite extensive and tbh I don't think we would have purchased the property if we had known about this. We have also lost the chance to object to the application as we weren't aware of it until after the period for comments was over. Obviously we are tied into the house purchase now, and we are going to be reasonable with the new neighbours as this isn't their fault and they have ever right to apply for planning permission and build on their land if approved. What I am wondering is, legally have the vendors done something wrong? If so, what can we do now going forward?