Hi Gadge re " All a vindictive neighbour can do is insist on his own surveyor monitoring the works at the instigators cost." Do you really see this as "vindictive" - I've been in circs where we agreed to the "one surveyor for both" route, the job screwed up (RSJ's poking through our living room wall), surveyor said "what is the problem just push them back" and we had to go to Small Claim Court for judgedment on reinstatement costs plus costs of the surveyor we had to appoint etc. Not much left of relationship with neighbour after that! Far better to have your own from the start as a warning expecially if there are structural issues (subsidence) or boundary issues e.g. they build their wall over your boundary when e.g. filling in half of a side return