Planning policy is a big topic with all sorts of legal and other ramifications. The good news is that it is possible to learn about planning policy at various levels improving your knowledge as you go along.
The main thing to understand is that commenting on planning applications should be as far as possible in terms of the issues that are dealt with by planning policy. Personal preferences and inconveniences don’t come into it unless they are related to matters which are specifically mentioned in planning policy.
Design and Access Statements (DASs). Major developments all require a DAS. In Hounslow DASs are also required if the site is within a conservation area and 100m² or more floorspace would be created. The idea of a DAS is it should explain in non-technical language. the reasons for the development and the reasoning behind the given proposal along with its main features. The Council for Architecture and the Built Environment (CABE) has produced advice on what should be in a DAS and how they should be written. You can find that advice HERE.
Given that DASs are supposed to explain the applications in a non-technical way for councillors and members of the general public and are supposed to be short it is a matter of concern that in Hounslow they are now very large documents which are not given to councillors on the Planning Committee and which they are not required to read.