It's all very well getting your planning permission approved but what if you see a planning application, for example, a neighbour is putting in a planning application and you don't like it, you want to object to the proposal, what can you do?
When a local planning authority receives a planning application, the law requires it to give publicity to the application in several ways. This allows those who may be affected by it to have to opportunity to make their views known. The advertisements of the publicity for the application quite often includes publishing a notice in a local newspaper, posting a public site notice as you'll see on gates/posts/fences and neighbour notification in form of a letter which is given to the occupiers and owners of adjoining properties.
You’ve got to remember the impact and balance of what the application is doing, you cannot complain about an application because you feel it might reduce your house value. Just because they wanted an extension, do bear in mind that what if you were in an identical situation and you wanted an extension on your house. Would it be unfair to object against theirs if you want to do it yourself? Once again, it's all about balance.
You need to write down your planning concerns and any relevant points then send them to the local planning authorities planning department. There is usually a case officer allocated to deal with each application. You can always send a letter to the enquiries desk at the planning department if you don't know who the case officer is, always try and include a planning reference number and the address on the application if you can.