On Tuesday, November 27, 2012 1:32:45 PM UTC, tim..... wrote:

You are obliged to enter into a party wall agreement with him

You both are, but often it doesn't happen.

Go see a properly qualified RICS surveyor, who will take on the responsibility for ensuring the structure does not damage your property. The side doing the work pay the bill under the PW Act. You need to serve the documents on the other side so that they don't crash ahead without approval.

He may be able to advise you whether you can object to the application or whether you need legal advice.

The planning application will result in your being flooded with offers from "Party Wall Surveyors". Do not sign any agreements with them, they are the scum of the earth and most have no qualifications.